We're nearing the end of the year. And I think about the only remaining PSP game that might be GOTY material is the PSP version of Warhammer 40K: Squad Command (we'll know how that shapes up next week - it's due around Nov. 13 or so).
My sort of "guess forecast" for PSP GOTY nominees includes at least some of these. I dug up Sony's official site for each game, for info's sake (beware some obnoxious Flash intros that take a while to load). I tried to break them down a bit by category, but there some genres (sports, racing, I don't really play or pay much attention to on PSP to this point). I put an asterisk by games not quite released, or just barely out (MOH: Heroes) that seemed to be shaping up well.
RPGJeanne D'Archttp://www.us.playstation.com/Jeannedarc/Final Fantasy Tactics: War of the Lionshttp://na.square-enix.com/fftactics/Disgaea: Afternoon of Darknesshttp://www.disgaeapsp.com/[Not really my cup of tea, but I've read a lot of
PuzzlequestI dunno-is it an RPG or just a fancy puzzle game?
StrategySOCOM: Tactical Strikehttp://www.us.playstation.com/SOCOMTacticalStrike/[I know I'm rambling on and on about elsewhere - it's so much fun and such a nice change from the relatively brainless SOCOM shooter PSP games to date, really.

If something like this was on PS3, I'd finally get one. IGN disagrees with me, but I still expect it to get some "votes"

]
Warhammer 40K: Squad Command *
http://www.squadcommandgame.com/[Just based on a pretty fun demo, but who knows how the full game stacks up].
ShooterSyphon Filter: Logan's Shadowhttp://www.us.playstation.com/logansshadow/[I haven't gotten it only 'cause I'm still trying to finish the first game

]
Medal of Honor: Heroes 2 *
http://www.ea.com/mohheroes2/features.jsp[Based on some really strong early reviews, and lots of improvements over the well rated MOH: Heroes]
Anyway, the next time some out-of-touch dunderhead slams your PSP because "there's nothing good on it," you can politely thrust this list in their face with my blessings.

I'll update this later. Man I spent an hour on this post. Gah. If you read down this far, you are rewarded with...
Blackjack's
Most Disappointing PSP Titles of the Year 
! [These were disappointing to *me*, so I apologize in advance if any of these is your Favorite PSP Game of the Year

It's all in good fun.]
SWAT: Target Libertyhttp://www.swatpsp.com/splash/I think I'm maybe the only person who bought this.

As much as SOCOM: Tactical Strike gets right about a tactical, actiony game (including a rich variety of environments), SWAT gets it wrong. Stick with
Killzone: Liberty if you want an isometric PSP shooter, and go for
SOCOM: Tactical Strike (just hitting shelves now) if you want a rich tactical-strategy/action game done right (imho). And write Guerilla Games about doing a Killzone: Liberty followup when Killzone 2 fails to be a "Halo-killer" (a 900-pound gorilla label, right up there with "WoW Killer" and "Diablo Killer," that probably no game can live up to.

)
Alien Syndromehttp://www.sega.com/gamesite/aliensyndrome/fullsite/index.htmlI hesitate to call this Most Disappointing "game" because in its own way, this got me back into PSP gaming (mine had gathered dusts for months until I rented and then bought this). But the environments are numbingly repetitive, the loot is actually excessive for such an arcadey shooter, and that the guy [Larry Holland] behind classics like virtually all of the X-Wing and Tie Fighter games, Secret Weapons of the Luftwaffe and the under appreciated Star Trek: Bridge Commander is reduced to doing a conversion of an ancient Sega arcade shooter-thon on Wii and PSP is... well.. sad.

The disappointment isn't the game, so much as that someone with that creative a track record isn't getting to do something a whole lot more ambitious (on any platform). I mean, imagine if Sid Meier did SWAT: Target Liberty.

(I know, maybe then the game would've been GOOD!)
Star Wars Battlefront: Renegade Squadronhttp://www.lucasarts.com/games/swbattlefrontrenegadesquadron/I'm renting this now. The controls are sloppy, the graphics are just not very good [especially compared to terrific looking titles like the Syphon Filter series, SOCOM: Tactical Strike, and the demo of next year's God of War: Chains of Olympus], the space combat's a mess, and most reviews are only lauding it for its multiplayer. Devs can do great work on PSP, but this just isn't a game I'd use to show off the system to a friend (just about anything listed above would better do that). It boggles my mind that Sony is bundling this game when there are so many excellent titles that better show off the system and have better thought-out control schemes.
A scaled down Knights of the Old Republic (turn-based stuff works better in PSP's limited button set) would seem like a great fit for PSP. I really wish they'd explore something like that instead of making a relatively mindless shooter that just demonstrates how clumsy this kind of game is on PSP if not done carefully.