Best Co-op rpg xbox 360 game?

my buddy and i are interested in getting a rpg that we can play co-op with via xbox live but i don't know of any. we played borderlands and loved it and we are also both fans of games like elder scrolls oblivion and dungeon crawlers/old school rpg style titles. dungeon siege 3 recently came out but it got mixed reviews so im not to sure if i want to invest money into it. does anyone know of any co-op rpg's that my buddy and i can invest hours into?