I thought he was asking between AC2 and ACB. :S I didn't realize he also wanted to know about the first one.
Yes, get the first one. It's pretty good. I've heard the PC version is better than the others, and gog.com has the AC1 - Director's Cut for the PC. --- "I hate these awkward moments..." - Ezio Auditore, taunting an enemy. "How can I regret the only life I've known?" - Altair Ibn-La'Ahad