I'll be up for some macrumors multiplayer also. Xbox name is same as my username.
Like you guys, I too was a bit disappointed in the title. But give it a few more hours. The plotline has started to pick up, and I'm at that point you want to reach in all video games, where you dont want to stop playing because you want to see what happens next. Also, i spent a lot of time just free roaming with a friend, and once you get used to the driving (although im still having trouble with 90 degree drift turns).
Coolest thing I've done so far is drive full speed through "Times Square" with four cops on my tail, did a quick 180, and while in reverse, shot out the lead cop car's tires, so he slammed into the other three, then did another 180 and drove off into the sunrise. Stuff like that is why reviewers gave this game a 10 ( i would give it a 9.7 personally, no game deserves a 10)
To Taustin Powers: There are hidden packages, because one of the xbox 360 achievements is to find all of them ( i think 100?) I havent seen any yet, but i havent played since i found out myself.