OCZ Reaper HPC 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Dual Channel Kit Desktop Memory Model OCZ3RPR16004GK - Retail
As far as I can see, you can't beat this deal for 4GB of DDR3 right now in Canada. It's DDR3 1600 with 7-7-7-24 timings, for less than most 1333/CL 8 kits. The only downside I can see is the high voltage (1.9V), and maybe not everyone is into the heatpipe look.
I bought a kit of this to go with my Phenom II X3 720BE processor and ASUS M4A78T-E motherboard. Some people have had to fiddle with this RAM to make it work properly, but it's on my mobo's Qualified Vendors List, so I don't anticipate too much hassle.