What Game to Play Next?

I've recently finished playing through Mass Effect and highly recommend this game! While it's not perfect and has a vehicle mode that seems like it was slapped on at the last minute, it's a must play for the rpg starved Xbox 360 fan base. It also has a very high replay value and achievements that can't be attained through a single time through. Once I finished playing Mass Effect, I started on BioShock. I haven't gotten very far into the game, but rest assured that I will play through it and eventually finish. The question at hand is this: What game should I play next? I'm seriously considering the Orange Box since I haven't played through Half Life 2 or any of the Episodes that follow up. Being the rpg fan that I am, I'm giving consideration to Lost Odyssey yet have found myself discouraged from it by the reviews it's gotten. Anyone played it yet? I take into consideration personal opinions as much as GameSpot's reviews. Eternal Sonata is another rpg I'm considering, but I'm interested in more than just rpg's. Anyone played Witcher? LOL, yet another rpg. Anyways, I'm in need of recommendations for my next Xbox 360 game or possibly PC game, in the mean time I shall be playing BioShock!

--Ace