According to a lots of reviews and sites Mass Effect 2 and 3 are where it really gets into a league of its own though. I've not played ME1 as I'm a PS3 owner and can't get it on that platform.
ME2 completely hooked me and ranks as the best game I've ever played as an overall experience. ME3 is currently in the same league as that. However, I'm still to finish it and make my final judgement based on the reportedly terrible ending(s).
ME2 completely hooked me and ranks as the best game I've ever played as an overall experience. ME3 is currently in the same league as that. However, I'm still to finish it and make my final judgement based on the reportedly terrible ending(s).