I took a quick look around Newegg.ca for you as I live in Ontario and I've been planning an $1800 machine for a while now. The tower I designed here was based on you already having a monitor and you not needing a DVD drive (does anyone actually use CDs/DVDs anymore?)
Rosewill Challenger Gaming Case with Rosewill Green Series 700W PSU (Combo deal for ~$115)
Western Digital Caviar Green 750 GB Sata II (~$50)
ASUS M4N75TD AM3 NVIDIA nForce 750a SLI (~$95)
2 x EVGA SuperClocked GeForce GTX 460 SE (Fermi) 1GB (~$300 for both)($60 in mail in rebates)
The final price including taxes and shipping to Ontario came to $800.16 and that price does not include the $60.00 of mail in rebates. Obviously I optimized for gaming and graphics. The reason why every single price is approx (~) is that I rounded all of them up to the nearest dollar to avoid confusion.