between those three games, you'll be wasted for months. fully exhaust mass effect 1 before moving onto 2, and you'll appreciate 2 that much more. there's 35 for ME1 and 30 for ME2. then dragon age, same deal - anywhere from 40-80 for DA:O, depending on how you play, and from 10-15 for DA:O:A.
you're set, dude =)
i might pick up witcher enhanced edition. i've got the disc for the original, but the patch that you have to get is 2 gigs and apparently only works about half the time. for the price...
edit: coop, you'll love the new KB games. i really enjoyed the first one, and goofed around with the second one a bit. lots of fun, albeit with a terrible plot.