For right now, here are some general suggestions of what I might build if I had that kind of budget. The two "big ticket" items would be the CPU, and the graphics card. But as a list of suggestions...[*:052e12c40a]The CPU would almost certainly be a Core 2 Duo E6600; at around $400CAD, it's pretty darn cheap for having a 4MB L2 cache, and you can overclock it pretty well on stock cooling; even without OC'ing, it's still more than any game short of
Oblivion can use.
[*:052e12c40a]Foir the GPU, you've got the cash, so I'd probably go for the GeForce 8800GTS, at around $570CAD, last I checked. Though its lead over the third-most powerful single GPU card (the X1950XTX) is only around 10-15% in
Oblivion, it's FAR beyond that in other games. Plus, though few have spoken of it, I wouldn't be surprised if you could push this card to act more like a 8800GTX. You SHOULD be able to fit this into your budget; if you can, you WON'T regret getting it.
[*:052e12c40a]The motherboard is important, but not quite ALL that important; go with a good chipset, and you really can't go wrong. the nForce 680i is pretty darn expensive, so perhaps you can do without it; it's primarily for heavy overclocking, anyway, and that can also be done on Intel's cheaper chipsets, such as the 965 and the like; $100-150CAD should get a pretty darn good LGA775 motherboard.
[*:052e12c40a]There isn't all that much need to splash money on RAM; yes, you do need a lot of it, but 533MHz (PC2-4200) DDR2 is just about the most expensive you'll really get a difference out of. Higher-priced brands, such as Corsair's XMS, or Crucial's Ballistix, are not necessary; RAM OC's rarely provide a meaningful performance boost for the extra money spent, so get a good, solid, affordable brand, such as Corsair's ValueSelect. I'd recommend getting plenty, though; 2GB is what I'd recommend, and should cost around $250CAD or so.
[*:052e12c40a]If you're serious about audio, while it actually DOESN'T provide all that major a boost to game perforamnce, get a dedicated sound card; a SounBlaster Live is pretty cheap, (old tech) though it's pretty much the same kinda stuff you can get in an Audigy 2 ZS. If you're even more serious, look to get one of the cheaper X-Fi cards; note that the "Fatal1ty" version with 64MB of XDRAM really doesn't provide a performance boost; the cheaper cards with only 4MB will do fine.
[*:052e12c40a]The last actual "perforamnce" part to list here is the PSU; with VERY few cases, the PSU that comes with a case can be considered garbage. One exception, though, that I will link to, is
Antec Sonata II. For around $120CAD, it's both a good, solid case, and comes with a 450w Antec SmartPower PSU; that's a good, solid PSU that can handle even a Core 2 Duo and a GeForce 8800GTX at the same time.
[*:052e12c40a]What you get for the drives is really up to you; at this current point in time, though, I'd say Seagate's drives are the best to get; their 7200RMP perpendicular drives are comparable in performance to WD's VASTLY more expensive 10000RPM Raptors. The current "sweet spot" for space is around 250-320GB; less than that, and you hardly save money (perhaps a couple of bucks) for a dramatic cut-off in storage space.Oh, and if you were hoping to fool me with that sort of thread, I apologize to have dissapointed you; as I mentioned, I've been doing this sort of thing as a hobby at multiple forums for a couple of years. (THG is just my favorite actual HARDWARE site)