Bang for buck = AMD/ATI build. Nvidia/Intel is nice, but overpriced for what they are.
I just built a computer with an AMD Phenom II x6 3.2 GHz and a ATI Radeon HD6990, wrapped it up in a tiny Apevia case (so small I had to take it apart to fit in the 6990) with an ASUS mobo, 2x4 gigs <m redline RAM, two terrabyte seagate HDDs (yeah, I know I didn't go SSD but I need capacity for my work), Blu-Ray drive, and a 900W Apevia power supply, saitek cyborg keyboard, gigabyte ghost mouse, and two 23" Samsung monitors for $2000 USD (so like $1950 CAD). Though for a budget rig I'd look at Dead Mike's suggestion. It's a solid build and a better value.
+1 Dead Mike