Assassin's Creed 2 is totally awesome. Yeah, I didn't even finish the first one because it was kinda lame and repetitive, but AC2 is awesome till the end. There's some bonus content that just came out for it, but it doesn't really add anything to the main story so I'd prolly skip it.

Mass Effect 2 is still super sweet. There's tons of great asshole moments (and some genuinely funny parts) so you'll like it Petersen.