Even the Geforce GTX 750 Ti would be fitting for a lower end desktop. I would also recommend more than 8Gb of RAM. I have 8Gb and want to upgrade to more because having 3 tabs open in chrome, BF4, and my mail running eats up 7Gb of it.

Overclocking to 4GHz isn't necessary. I have a 3.2GHz core i5 and I can TELL the difference from 1.6 GHz (which is an old laptop I have). Overclocking is something you might not want to do DARCA, as most new PC builders don't do it and it can damage your system (though done right, there is almost no chance of this).

Yaaay I guess I win the award for most dated machine!  Compared to what I've seen on this thread, mine's a fossil

P4 CPU 2.03 GHz, 1 GB RAM, NVIDIA GeForce 7300 GS, Win XP SP3.  CIV4/Colonization and GalCiv2 run very well.

In truth, while my desktop system has given me 7+ years of great service, I am long, long, long over due for a new one, and I am in fact currently prowling the market for something powerful enough to give me 3 to 4 years of excellent service -- without breaking my bank account.

Yep, the advent of Galactic Civilizations III has forced my hand to reach for my wallet...

I'm not sure sure what video specs to watch out for, but 8 GB RAM and 64-bit dual core should do I think, or is quad the wiser option?  Budget conscious suggestions welcome

Edit: lots of good advice I see above already.

I think you have gained budget wise by having obtained a system that has lasted such a long time. And you will do so again if you plan for a long haul with your new one.

You may wish to compare two computers as similar to each other as you can get to the only difference being 8G of ram and 16G of ram, then compare two computers with the only difference being as close as you can get being one with a dual core and one being a quad core. Look at the differences in price and I think you will find that the differences are too miniscule for short sighted planning. The lesser memory and less capable CPUs may be a tad cheaper, but I think you would run out of machine much faster, costing you more in the long run.

Also, I would apply the same reasoning on hard drive space. Windows 7 (which may not even be available these days) and Windows 8 use a lot more RAM and hard drive space than XP did, just for the OS. I would say a minimum of 16G Ram and 1TB hard drive would be minimum needed to satisfy long range planning.

Dude are you living in a third word country or something? If thats the case I understand but ive found faster computers in the trash. Not even joking. I was walking on the street two years ago and there was this pretty tower just there along the trash bags. I took it home and in it there was a p4 3 ghz, 1.something gigs of ram and a geforce 7800. Now, you could just go to the nearest flea market and find something twice a powerful as you have and haggle it to under 20$.  

Now, if you are looking to build a decent PC on a budget there are many wise tricks to do it smart and cheap, dont listen to guys like ParagonRenegade, they are  insane. Maybe if you tell how much you would expect to invest I can give you a few advice accordingly.

All this being said, my hats off for having used that computer for so long! I still have my 486 from when I was a kid, I still fire it up once in a while

Would it be possible to build a good box with about $500?  I noticed OS (Win 7 Pro) and a decent LED monitor would together add another $400-600.  I have friend who is a GalCiv freak and he is in the same boat: needs a new system -- he saw online Alienware units from $799 to $2499.  Catchy brand theme, but I'm not sure about them; I prefer to build mine and help my friend with his too -- we have several PC shops in town where you can get parts.  I'm competent enough to put something together, but judging brand quality and what is a reasonable price for parts I'm not sure since it's been a while.

Going quad core with 16 GB RAM seems like the wiser benchmark to aim for...

Well, agreed that ram price is not very expensive nowadays, but you don`t really need more than 8 gb right now, 16 is not really necessary for most stuff, including all games I know.  So that can easily cut 60-70$ or more off the bill. I just noticed you are a fellow canadian! Tomorrow I will check out a bit for you and see what I could recommend for 400-600$ that is available in Canada. Maybe if you want to reveal your city I could check more specifically.  

One quick advice I can give is Consider second hand gear.  You should check your local Craiglist/kijiji for some deals. I made some really good deal by going in the second hand market. For instance you could find ParagonRenegade's previous PC that is likely still very good for a total steal!

Also, for graphic cards, at least for Nvidia ones, avoid the budget models. For example, you are better off with a second hand Non budget 400 series ( Such as GTX 460) than the newer budget model in the 600 series that would cost more and offer lesser performance. Those budget cards are usually highly crippled and they lure customers with ultimately meaningless features. 

Taking potshots at me every chance you get, lol

Case: Cooler Master 932 HAF w/ 3x 200mm Cooler Master Megaflow Silent Fans

PSU: 850w Antec 80+ Gold Modular

Motherboard: Gigabyte GA-Z68X-UD3H-B3 (rev. 1.3)

CPU Cooler: Cooler Master Hyper 212 Evo w/ Dual Fans

RAM: Corsair XMS3 16GB DDR3 1333mhz

Graphics: Evga 770 GTX 2GB SC w/ ACX

HDD: 120GB Samsung 840 Series SSD, 500GB WD HD

Optical: LG BluRay Combo Drive w/ M-DISC

Monitor: ViewSonic 26" LCD 1920x1200

Fan Controller: Akust 5 Fan Controller

Case Sound Insulation: Akust silencing foam

Human Input Devices: Logitech Illuminated Quiet Key & Logitech G9 Mouse

And when I feel like it, I can use my TV as a monitor.

Model: Alienware 18 (Laptop)

CPU: Intel i7-4700MQ (6MB Cache 3.4GHz TB)

RAM: 16 GB Kingstom HyperX 1600 MHz (1.35V LowVoltage)

Graphics: Dual (SLI) NVIDIA GeForce 780M GTX

HDD: 512 GB Samsung 840 Series

SHDD: 128 GB Corsair Force 3

Cache Drive: 64 GB SSD

Sound Card: Realtek HD Audio

Bluetooth Device & DVD Drive

Monitor: Default laptop: 18.4" WLED FHD 1920x1080 TrueLife Display (Sometimes use my 60" Samsung TV)

External 3.0 USB 1TB HDD

Mouse: Logitech G602 Wireless (AMAZING MOUSE! I )

Keyboard: Standard laptop but sometimes Logitech G710+

Sure, why not. 

Windows 8.1

Corsair 900D

PC Power & Cooling 1200W Silencer MK III

Corsair Dominator 32 GB RAM

MSI Motherboard BIG BANG-XPOWER II X79

MSI GTX 690

i7 3960X @ 4GHz cooled with dual Aquacomputer Airplex Radiators

Sound Blaster X-Fi Titanium HD  

Triple overclocked Overlord Monitors

Samsung 512GB SSD

Bluray RW

32 gb ram? Holy crap that was the size of my hard drive 12 years ago.

No alpha for you!!!

OK! I'm going out to a few stores today and I actually have a good plan...maybe. 

I've had a steam account for about three days, so I don't know much. I made a account on my soon to be old computer. If I became a founder before I have a new computer, would my old computer be the one I would have to play on. Or could I DL steam again on the new computer and use the same account I have.

I am going to look in some stores today, and I'll look for a 4core and i5 3GHz processor which seems normal. (for a few more years) and a good battery life. (those two in one tablets looked good )

Now this is the creative part. Why buy a expensive computer with a Tera byte hard drive and 16GB of RAM? When I can buy all that online and save hundreds!!! http://www.crucial.com/store/mpartspecs.aspx?mtbpoid=724A5E0DA5CA7304 (has anyone had experience with this site?) I can buy RAM ,and there is no way I would need a big hard drive, as my computer of three years I've put about 50GB on the drive.

I did look at the sites you all linked for me and they were great, thanks. Also, everyone gets karma for helping me again.

DARCA

Digital downloads are tied to information you provide, like your username/password/whatever, not to your hardware. I personally had a laptop before my current desktop, and I re-downloaded everything I had on the old laptop without any problems.

Don't take any shortcuts when it comes to buying/building computers, it bites you in the ass.

Exactly! Build your own computer DARCA, my advice to you. You can get a very good one for $700.

Modern games will quickly fill up your hard drive, especially if you have ten or more. I highly recommend you get at least 1 GB.

:3

You mean games you purchased on one system, you got again on another for free. And I can do that for this game to. If that is the case I will sign up today.