I took a look on Gamefaqs for most of your recommendations thus far...
Pixeljunk Shooter and its sequel are wonderful.
Flower is pretty delightful.
Uncharted!
A.C.E. R sucks. The robot game you want is Gundam: Extreme Vs., which comes out next week or something.
I don't get what kind of game
Pixeljunk Shooter is. I guess they're side-scrolling shooters, is that correct? Are they on the level of Gradius and R-Type?
I've already been dead set on A.C.E. R, but I have heard it's pretty disappointing. :/
Is
Gundam: Extreme Vs. like Gundam Vs. Gundam for the PSP? While I enjoyed that game a little bit, it wasn't high up there for like Gundam Battle Royale or Senjou no Kizuna.
Will definitely second Uncharted. Fun stuff, to be sure. Uncharted 2 was mind-blowing, in a Hollywood blockbuster sort of way.
I'll recommend 3D Dot Game Heroes, since you're a Zelda fan. It's very much in the old-school Zelda vein, and the game is relatively inexpensive right now.
The Ratchet & Clank games are great, as well. You might find a deal on those right now (at least the ones that aren't All For One). Also, Valkyria Chronicles. I've not been able to sink much time into the game, but if the idea of a sort-of X-Com-esque strategy game with you getting to manually aim, set in a kind-of WWII anime motif appeals to you, by all means, go purchase it right now.
Some folks here didn't like FFXIII. I actually did, although be forewarned that the game for a long time is very linear. I still like to call it a corridor RPG-RTS. 
My brother played a lot of the Infamous games. They're pretty good, and from the developer of one of my favorite last-gen platformers, Sly Cooper.
For some reason, I like Folklore a lot. Definitely worth a look. And while I'm thinking of that game, Majin and the Forsaken Kingdom is a great game as well (it's multiplatform, by the way).
If you're a little more masochistic, you could look at Demon's Souls and its follow-up, Dark Souls. The first one is the only one I've played a little of, and it kind of made me feel a little like playing a game NES-style, with the amount of caution you have to exercise to survive.
And, finally, another multiplatform release in Darksiders. I enjoyed it, even if it's not wholly original. It's basically God of War-meets-Zelda, with a very comic book-esque representation of the Book of Revelations (which means it makes no sense at all, but whatever). And if you enjoy them, you can pretty much play every single God of War game on the PS3, what with all the various collections out there now.
Whew! I'll stop now. 
I've seen ads for
Rachet & Clank, but I'm not sure what to make of them... They look like platformers ala Jak and Daxter (for which I played two of the PSP games and found them to bore me), so I didn't think about it.
Valkyria Chronicles looks interesting. So, it's a strategy RPG set in WWII, but there's action sequences? I don't get it much though. When I think strategy RPGs, I think Fire Emblem and Super Robot Wars, which I like; but those don't exactly give you a chance to manually aim or anything- and sometimes that's for the better!
I've seen
Majin and the Forsaken Kingdom several times at Gamestop but it always felt like it was a sort of tie-in to some cartoon I've never heard of. Looking at some of the screen shots, it looks like it's been inspired by Shadow of the Colossus/ICO in several ways. I'll be looking for comparisons on this game later to see if it's better for PS3 or not.
Didn't even bother looking into
Demon's Soul and
Dark Souls. The way you present them, it makes me feel like it's the type of game that will suck the fun out of me because I will need to give it a lot of time or need mad skillz of the sort that Ninja Gaiden requires.
I took a look at
Darksiders and I see a lot more God of War in it than Zelda. I'm not sure what to say about that, since I actually did enjoy God of War on the PSP a little. But it's the kind of game that I would play on a handheld and forgive some of the repetitive design simply because it's not like I play for stretches at a times- but on a console, I may just grow tired of instantly. Maybe I'm wrong. So,
how much Zelda is there in Darksiders?Regarding multiplatform, it's your preference. You can check lensoftruth.com for Head-to-Head analyses of major games, which sometimes reveals dramatic quality hits in versions for one platform or the other, but generally it comes down to personal preference. Personally, I prefer to play my multiplatform games on the 360, for two reasons: I know more people who use Live than PSN, and I prefer the 360 controller to the PS3 controller (the 360 pad is heftier, and the shoulder triggers are concave instead of convex. Seriously, who thought convex shoulder buttons was a good idea?)
For exclusives recommendations? 3D Dot Game Heroes is fun! Demon's Souls, if you're hardcore. Folklore is probably the best action/rpg on the system, and basically plays sort of like an action-oriented Megami Tensei title with a heavy Celtic bent in its mythology (as opposed to the usual Buddhist/Judeochristian/Hindi angle) though it is pretty linear dungeon-crawly. inFamous games if you like open world stuff. The Ico/SotC HD collection is great if you missed one or both of the games on the PS2. LittleBigPlanet (2) if you want to play around in a creative environment. And yeah, totally Uncharted. #2 is the best game in the series, followed by #3 and #1. #1 is still pretty good, but it suffers from too many gunfights with too many goons that absorb too many bullets before they die.
It may or may not be your sort of thing, but I really enjoyed Aquanaut's Holiday: Hidden Memories. If you can find it you can even import the Asia/Chinese region of the game, which will display (broken) English on an English-language PS3. But it takes a very particular player to enjoy something like that.
I already bought me 3D Dot Game Heroes the moment I bought my PS3.

It was one of the games I'd coveted for a while.
Folklore does look interesting, but is the linearity that bad or is it the sort of linearity that let's explore a little but keeps from going off-track, such as the RPGs from the SNES (ie Final Fantasy and Dragon Quest)?
I'm not that much into open world stuff, although my sister might enjoy
inFamous a little bit.
I have been thinking about the
ICO/SotC bundle! Is it the same game with a face lift or have some things been improved? Either way, SotC was breathtaking for the PS2, I can only imagine how it'll look for the PS3. And I haven't played ICO, so this is a good excuse to nab both since I have neither one.
I have thought about getting
Little Big Planet, but then I remembered that it was fun for a little bit and with friends; but alone, and for the PSP, it got boring and repetitive after a while. I never played LBP on my own for the PS3 (it's always been with friends), so I'd like to know how well the single player is, or is it as bleh as the PSP version?
All three of you mentioned
Uncharted, and I've heard some things about it, such as it being to games what Indiana Jones is to movies. So, Uncharted 2 is the one to get? Are they connected games or are they disjoint, such as the Final Fantasy series? And... just what genre are they? I can only imagine them being adventure games, considering the comparison I've heard.
I took a look at
Aquanaut's Holiday... and I feel like it's a game that would simply put me to sleep. Given that I'd have to import it, it's not like I could just throw some money away to try it out either. :/
Last thing: Gid, thanks for the site. I took a look through it and, even though the site seems clunky and unwieldy, I think I know which version of Batman Arkham City I may be getting in some future.
