Yeah guys I finally beat it a couple days ago. One of the best games I've ever played and I've been gaming since TMNT on the NES....
I did pick up a copy of ME1 for $20, and just ran through the story (<10 hours). Definitely glad I played ME1 first.
I could list the pro's/cons of both, but I'm too lazy. Head over to the ME2 forums on Gamefaqs if you want answers.
Epic game.