Building a gaming rig, got a few questions

[plucesiar]

Hello everyone! This is my first time building a computer. Here's a list of preliminary information:

Country: Canada
Stores: Newegg.ca (yes it's finally here!), TigerDirect, NCIX, and local shops including CanadaComputers
Budget: $1000-1500 CAD, obviously cheaper the better (I'm still a student)
Games I want to play: Empire Total War at max (or near-max) setting, Crysis, Farcry, GTA, etc. Hopefully be able to play games released in the next 5 years
Parts already have: OS (Windows XP Professional), Mouse, Keyboard
Brand Loyalties: No, as long as it's a quality product.
Overclock CPU: I've never done it before but I'm willing to as long as there's instructions and it won't screw anything up, like computer lifespan.
Do you want a system that supports SLI or Crossfire?: Not mandatory. From the research I've done it seems like for the average gamer it's better to just get a really good video card than to get 2.
When do you plan to build it?: Last week of April 2009.


So, here's the rig so far:
(prices are in CAD and does not include tax and S&H and does not factor in any MIR)

CPU: Intel Core 2 Quad Q6700 Processor, 2.66GHz, 1066MHz FSB, Kentsfield ($260)

CPU Cooler: MASSCOOL 90mm Ball ($13)

Mother Board: Asus P5Q Motherboard ATX ($180)

Video Card: EVGA GeForce 9800 GTX(G92) 512MB ($186)

Power Supply: OCZ GameXStream 600W ($120)

Memory: G.SKILL 4GB (2 x 2GB) DDR2 1066 ($56)

Case: NZXT Apollo Black ATX Mid Tower ($85)

DVD Drive: LG Black 22X ($31)

Hard Drive: Western Digital Caviar SE16 7200RPM 500GB ($71)

Monitor: 15" Viewsonic LCD Monitor (Already own)

OS: Windows XP Professional

Price before Taxes, S&H: $1003 CAD
Estimated price after taxes, S&H, and random things I might pick up on the way: $1300 CAD




And I've got just a few more questions:
1. Should I switch my case with the Cooler Master RC-690 (at $100)? The Cooler Master seems to be a lot more popular.

2. This is probably a dumb question, but will my GeForce 9800 GTX fit in the NZXT or Cooler Master Mid-tower case? What about the motherboard?

3. Any recommendations for a motherboard/processor? How upgradeable is it?

4. Any recommendations for the PSU? Should I get more wattage?

5. Should I get one of the super-high-end GPU's like GTX 260 or will the GeForce 9800 GTX do just fine for the next 3-4 years?


Please give me your comments/suggestions! Thank you everyone!

Also, just a thanks to Phoenixx45, got a few ideas from his setup.

 

[xthekidx]

On a 15" monitor, a 9800 GTX will play anything. If you plan on upgrading your monitor any time though, you will need more power most likely for Crysis. I would use an ATI card so that you can crossfire later, maybe go with a 4830 right now, then when you decide you want a 22" inch monitor, add another one in crossfire. I would recommend getting a Corsair 650tx, the ocz PSU's are ok, but not the greatest quality.