PSP must-haves?

[okr]

3 unique PSP games:
Lumines: Puzzle Fusion
LocoRoco
Patapon

Not unique, but fun on any system:
Lemmings
Sid Meier's Pirates!
(PSP port of the 2004 remake; I still like the first remake "Pirates! Gold" from 1993 more, but the latest remake is fun as well)