I started playing the first "Assassin's Creed" today. Holy crap, what a boring way to begin a game!
As it happens I just bought AC 2 in the steam sale (currently downloading.) I ummed & ahhed about getting the first game as it was on the cheep too, but after reading several reviews and a half dozen forum threads with the OPs asking if they should play AC1 or skip straight to AC2...I decided not to bother with it.
The consensus appears to be that the only value the first game has is to clue you into the plot and is *highly* repetitive and unrewarding. I'll just watch the cutscenes on youtube to get caught up and skip the 10 hours of tedious gameplay.