Some of the best games-as you might guess-are some of the most expensive. Setting price aside, here are some I would recommend.
Jak & Daxter trilogy and Jak X Combat Racing
Ratchet & Clank trilogy, Deadlocked and Secret Agent Clank
.hack series (7 games total)
Final Fantasy X, X-2 and XII
Dark Cloud 1 & 2
Rogue Galaxy
Sly Cooper trilogy