How many people have you recruited? You should be able to get a good 40 hours if you play it fully. Make sure you get all the DLC too, especially lair of the shadowbroker.
Dave
Ah, you've got plenty left to go then, if you get/have the DLC, you'll get another 2 more characters and loyalty missions to play through. Sounds like you've got Mordin and Garrus then.
Definitely worth playing, you can get ME1 on pc for dirt cheap now days as well.