u2jedi: Infamous Duology
Killzone Trilogy
Reistance Trilogy
Siren: Blood Curse
Uncharted Trilogy
Dust 514
I've only had my PS3 for a few weeks but I'll use this occasion to pretend to be an expert. :B
Infamous is totally awesome. My favourite sandbox game on PC to date was The Saboteur and I must say that Infamous is surprisingly similar to that one. There's no driving but but climbing and the super powers are awesome, also some of the tasks are pretty cool. I'm about to finish my first run through the game (I'll probably go for an "evil" run on hard mode soon after) and I'm loving it.
Resistance 1 was also one of the first games I got for the PS3 and I must say, it was incredibly disappointing at first. First it looks and feels like a poor man's Call of Duty (a VERY poor man's CoD as the graphics are really bad for a next gen game), later on like a poor man's Halo but once you get the hang of all the weapons it's REALLY fun. The plot is mediocre but the scenario is cool (basically WW2 with aliens, yay!). Also it has split screen coop adding to the fun (removed from the sequels, though).
About Uncharted - well, I've played the first one at a friends place (about half-way through) and I was very disappointed. The "adventure" part is trivial compared to other action adventures, the shooting is awful compared to "real" shooters and the plot is absurd. And not like "over the top, but cool!" but more like "the writers are friggin' stupid!".
And Dust 514 - well, I've played two matches and I was so disappointed that I instantly uninstalled it (after many hours of downloading, installing and patching). IMHO it's trying pretty hard to hide the fact that it's just a mediocre Battlefield clone with ridiculously complex character customization (which may swallow much more money than you'd pay for BF, as far as I can tell). I thought that despite the mediocre reviews I'd enjoy it but I just didn't. Heck, I even had more fun playing Resistance 1 multiplayer. :P
Anyway, another exclusive you may want to add to the list is God of War. I've only beaten the first one so far but I was having a great time - it also reminded me a lot of the Sands of Time trilogy which I loved. Can't wait to check out the rest of the series.
u2jedi: I see that the Playstation 3 has had 4 design revisions. Do you guys prefer the new 'slim' or the old 'slim' (the 160GB one)?
Well, I've got the new Super Slim (the one without an HDD, only 12 GB flash drive but you can easily insert any 7,5 mm HDD with 5400 rpm if you get the "mounting bracket" which costs about 10 bucks). Anyway, I must say that the new designs got uglier and uglier. I really liked the looks of the original PS3, also the Slim was still okay, the Super Slim on the other hand is quite an ugly box and it has a top loader, which is a little awkward since you have to manually close the drive and you need space above the console if you want to see where you're putting the disc. :P I'd recommend going for the Slim.
Narakir: There is a way to make your PS3 and PC share the same screen and speakers actually, it just need for you to have matching equipments. That's why I did and I'm pretty happy about being able to switch to one or another just by pressing one button.
You mean an HDMI switch, right? I'm considering to get one eventually. Would be cool if you had some advice.