I'm gonna give you my list of Top 20 PSP Games (or Must-Have psp games)
Final Fantasy: Crisis Core 20
Dissidia Final Fantasy 19
Silent Hill Origins 18
Killzone Liberation 17
Soul Calibur Broken Destiny 16
Tekken 5: Dark Resurrection 15
Wipeout Series14
The Warriors 13
Tony Hawks Underground 2 Remix 12
Rock Band Unplugged 11
Jak And Daxter: Lost Frontier/Daxter 10
Burnout Series 9
Motorstorm Arctic Edge 8
Metal Gear Solid Portable Ops/+ 7
Gta series 6
Syphon Filter Series 5
God of War Chains Of Olympus 4
Gran Turismo 3
Resistance Retribution 2
Monster Hunter Freedom series 1
All of these games deserve (in my opinion) a 9/10 minimum as they're all the best Handheld games ever made. Compared to ps3/ps2 versions perhaps the score would be more of an 8.5/10 because of perhaps one or two things lost in translation but otherwise, they raise the bar in terms of quality handheld gaming.
Also, games to check out that are coming out soon:
LittlebigPlanet, James Cameron's Avatar, God Eater, Dante's Inferno, Kingdom Hearts: Birth By Sleep, Phantasy Star Portable 2, Invizimals, Metal Gear Solid Peace Walker, Socom 3, Assassins Creed Bloodlines and more.
And lastly, here's the link to my video!
link