I feel I'm hopelessly out of touch when it comes to good games on PS2 - apart from Gradius and God Hand. As my 360 has been invaded by my niece and nephew, courtesy of SONIC, I thought I could get my fix of self-indulgence on PS2 instead.
I liked the look of the SEGA AGES release of Galaxy Force II (LEFT TURNNN! RIGHT TURNNN!) so that is on order - but what else is worth playing these days?
Galaxy Force is VITAL.
As are Devil May Cry 3 - which in terms of mechanics still hasn't been surpassed, and Psyvariar 2 which is a brilliant version.