Mass Effect 2 is hands down the best RPG I've played this generation. As much as I love Dragon Age and Eternal Sonata, and to a lesser degree Lost Odyysey, the world that the loremasters at Bioware created is something special. Its the best sci-fi stuff I've played/watched/read in a long time. I was so into it after the first game that, besides playing through it about 4 times in a row, I went out and bought 2 books(which were written by the lead writer for the games and are thus excellent).
I went through once and loved it, and managed to not have anyone die. I'm going to go through it a second time to get the hard mode achievement as soon as I'm done with my current games. Bioware is becoming my favorite RPG company of all time...with Star Wars K.O.T.O.R. and Dragon age, and of course the Mass Effect titles, they haven't put out a bad game yet and are on their way to dethoring the mighty Square if they keep this up for a while longer