Yep, that's how it works.

THIS is the best way to build a PC from online parts.

For a $704 decent computer build. (you could shave some money off with buying from other sites or a different case)

GPU: Geforce GTX 750 Ti 2GB http://www.amazon.com/EVGA-GeForce-Dual-Link-Graphics-02G-P4-3751-KR/dp/B00IDG3PRI/ref=sr_1_2?s=electronics&ie=UTF8&qid=1395271515&sr=1-2&keywords=geforce+gtx+750

RAM: 8 Gb Kingston Blu http://www.amazon.com/Kingston-Modules-1600MHz-Non-ECC-Desktop/dp/B0057Q4ADU/ref=sr_1_4?s=pc&ie=UTF8&qid=1395271450&sr=1-4&keywords=ram

PSU: Rosewill 450W 80 Plus Gold http://www.amazon.com/Rosewill-Certified-Power-Supply-CAPSTONE-450/dp/B006BCKDGW/ref=sr_1_3?ie=UTF8&qid=1395271239&sr=8-3&keywords=450+w+psu

Case: CoolerMaster HAF 912 http://www.amazon.com/Cooler-Master-HAF-912-Computer/dp/B00BCXF6O4/ref=sr_1_2?ie=UTF8&qid=1395271251&sr=8-2&keywords=cooler+master+case

Mobo: ASUS Z87-K http://www.amazon.com/ASUS-Z87-K-DDR3-1600-Motherboard/dp/B00CRJSWPC/ref=sr_1_9?ie=UTF8&qid=1395271161&sr=8-9&keywords=asus+mobo

CPU: Intel Core i5 @ 3.0 Ghz http://www.amazon.com/Intel-i5-4430-Quad-Core-Desktop-Processor/dp/B00CO8T9VC/ref=sr_1_5?ie=UTF8&qid=1395271277&sr=8-5&keywords=core+i5

HDD: WD Blue 1 TB http://www.amazon.com/WD-Blue-Desktop-Hard-Drive/dp/B0088PUEPK/ref=sr_1_1?ie=UTF8&qid=1395271357&sr=8-1&keywords=WD+blue

If you have any questions, let me know! The PC part picker (above) will search other sites for these same components for cheaper prices.

Here's to the PC Master Race.  

Edit: P.S. I put this together in 10 minutes, so these items could be refined.

I Second for PC part picker, but be careful to set your country to canada as prices and availability change from US to Canada. 

Overall I think your selection is fine but I would advice against that video card. It is a budget model.  It offers performances similar to a GTX 560 ti which can be found for around 100$ on ebay. Although the 1 gb is most common, it can be found in the 2 gb flavour. Also, you can regularly find GTX 660 cards on ebay for around 150$, which is a significantly better card with double the memory bandwidth.

Heck, even an ASUS GTX 460 when overclocked ( That card overclocks to 900mhz), which can be had from 50-70$ used is nearly a match for a GTX 750 ti, if you overclock it of course.

Also, if you look around a bit you can find better ram for similar price. I paid the same for ram that is rated 2400 mhz. ( I know you did this quickly but just saying )

I also find 450 w PSU to be somewhat weak.

-Lastly, It is possible to reuse an old case to save a few moneys. And possibly the PSU. This is what I did with my last build.  I went to CraigList, bought a Core 2 quad PC from someone for 450$, sold the CPU, RAM, Video card and mobo on ebay for the same I paid and I ended up with Case that was originally worth 300$, a 1200w PSU, DVD burner, Sound blater X-FI, 2x 1 tb hard drives (RAID!)  and windows 7 Install disk basically for free. Ok I was a bit lucky there.  But my point is always look for sneaky deals!!

I think I like the HP Envy as my new laptop.

More importantly I am going to be a pledge to be a SD founder after write this message!

DARCA

 Windows 7 Home 64 bit

Intel Core i5 760 @ 2.80 GHz

GeForce 650 GTS

Antec GX70 or something, it looks like a shitty military deco case but it was cheap and has pretty good air flow but it is Gaudy as hell.

1TB Wester Digital HDD

8GB Ram

I love building computers but I hate spending money so I tend to buy budget parts.  If I had a bigger budget to spend then I would do a lot more research but honestly, my rig can run everything that I play, which generally doesn't have super crazy requirements, High - Ultra so I am currently content with what I have. 

Most rigs I will generally buy cheap parts and then toss whatever upgrades I need to run a new game. 

Oppps.  I think you mean 1 TB.

System Specs:
*Home Built*
Coolermaster Haf X Desktop

Coolermaster Silent Gold Pro 1200watt PSU

ASrock Extreme 9 Motherboard

Intel Core I7 3930k @ 4.5 GHz

Patriot Viper 3 16GB RAM @ 2133Mhz

Intel 520 SSD 240 GB

Western Digital Cavalier Black 1TB 7200rpm

LG 24x CD/DVD drive

Sapphire 7970 Vapor X 6Gb @ 1200Mhz Core, 1720 Mem

Custom XSPC Raystorm Watercooling CPU Loop Coolermaster 2x blue led 200mm top exhaust fans, 1x red led 200m VGA Intake fan, 1x red led 230mm Front Intake fan, 1x blue led 140mm power exhaust fan.

Logsis Red and Blue cold cathode lights

Asus VW246 24 inch LCD Monitor 2ms

Razer Black Widow Ultimate mechanical keyboard

Razer Naga Molten edition Mouse

Audio Technica Pro 700MK2 Headphones

 AND/OR!

Asus G75VW-DS72 Laptop

17.3 LED 1080p Matt Display

Intel Core i7 -3610QM Processor 2.3GHz

16 gigs SO-DIMM DDR3 Ram

Nvidea GTX 670M 3 gig GDDR5 Vram

256GB Solid State Drive + 750GB 7200rpm Hard Drive

White Keyboard Back-lighting

Blu-ray Writer+Burner

Windows 7 64 bit Home Premium

8.7 pounds

8 cell Lithium Battery

I'm really eager to test the alpha on two different platforms. Wanna push them to the limit!

The game belongs to you, not to your computer. You can play it on any computer if you log in to Steam (or have already done so once and can go into offline mode).

That's kind of the beauty of Steam. I go somewhere, and my entire game library goes with me. I buy a new computer, and a couple of clicks puts my favorite games back on it. Baby breaks my DVD in half because he got into the case somehow? Steam doesn't care.

So, yeah. You get it on any computers you want. Steam only cares that it's your account.

Also, you can copy your entire steam library to a new computer with say, an external hard drive, and steam will just use the data and you wont need to redownload the games. Unlike *cough* GOOGLEDRIVE

Think about it. Back in the day, when games came out only on CDs or DVDs, you could put the game you bought on any PC you wanted to, and if you replaced a PC you still had the CD and could put the game on the new PC. StarDock's procedures for buying online has always recognized that by simply recognizing your copy with your logon/password identity. That was all that was needed to reload your game on any PC.

In addition, Steam will let you play your copy of the game on only one PC at a time, at least if you are playing in single player mode (I have no experience with how they handle multiplayer).

It's the same, your account can only be playing one game (in one location) at a time.

I should now have a founders badge. Dose everyone see it?

DARCA

I'll see if I can get into the vault.

Sorry DARCA, no badge yet.