I'm posting this on the eve of AC2 release. Hopefully I will be there at midnight picking it up.
The first one was awesome. Some say it got a little repetitive, but the free running and climbing was awesome. Ubi did an incredible job rendering the cities of Jerusalem, Acre and Damascus (can't remember the others). The story line is also very compelling, and melds very well with the actual history books. If you haven't played the first, I highly recommend it. I know that it's available for download on XBox Live. Not really sure about PSN.