I show off some awesome PSP homebrew games and apps. I may put links for all of them later on. Enjoy and hope this influenced your choices of what you want on your PSP.

EDIT: As requested, here is the theme I use and the plugin to run it (NOTE: CFW Required)
http://sh.st/QxCJW
I will make a tutorial later for using plugins and themes..
EDIT: Here are some link to the homebrew (NOTE: Some homebrew require CFW!)
Nazi Zombies Portable: http://sh.st/QxC2m
All Emulators:http://sh.st/QxC7h
Doodle Jump: http://sh.st/QxBZE
Lamecraft http://sh.st/QxNfl
Cat Mario ( Syobon Action): http://sh.st/QxMD8
CSPSP: http://sh.st/QxMn1
DoomPSP: http://sh.st/QxMLi
QuakePSP: http://sh.st/QxM1u
Tyrian: http://sh.st/QxM5l
Kurok: http://sh.st/Qx1aM
No Bugs Allowed: http://sh.st/Qx1qA
Kitten Cannon: http://sh.st/Qx1yQ
Duck Hunt PSP: http://www.moddb.com/games/duck-hunt-...
PSPInstaller 10: http://www.mediafire.com/download/agd...
(NOTE: Most of the game I have above PSPInstaller came from it.)
Angry Birds:http://www.mediafire.com/download/4b8...

EDIT: Here are some games that are included in PSPInstaller for those who can't access internet through their PSP or just don't want it. I still highly recommend downloading PSPInstaller because it is way more efficient than these links but here you go (NOTE: The emulators come with some ROMS I have on my PSP so I hope you enjoy those):

Geometry Wars Portable: http://www.mediafire.com/download/hkj...

Minicraft: http://www.mediafire.com/download/y05...
AdhocFileTransfer: http://www.mediafire.com/download/l2h...
FCEUltra: http://sh.st/Qx2x6
gpSP:http://sh.st/Qx2kf
psp2600: http://sh.st/Qx2uT
Silver Edge: http://sh.st/Qx19X
The World's Hardest Game PSP: http://sh.st/Qx153
Wolfenstein 3D: http://sh.st/Qx1Vx
Xplora 2: http://sh.st/Qx1ZH
Zombie Crisis: http://sh.st/Qx1Dq
Zelda PSP Trilogy: http://sh.st/Qx1Pu