Doing the various loyalty missions now, about halfway through ME2. I thought these games would keep me occupied till ME3 came out, epic fail.
They're both pretty short. If you stick just to the main storyline of ME1 and don't do a lot of sidequests, you can finish it in under 10 hours. I know that my first runthrough of ME2 was just under 30 hours, and I did most of, if not all, the sidequests (but this was prior to the meaty DLCs).
They've never been presented as these epically long games.