If all you need is stereo in/out then the MBox is a good choice. I only use the MBox for mixing sessions while laying in the bed at three in the morning. Laptop, MBox and headphones and I can mix and edit sessions into rough mixes( I wouldn't suggest doing final mixes on headphones). I have also used the MBox for vocal overdubs occasionally while out of the studio. All in all I'm happy with the MBox for what I use it for but I also have the Digi002 which is my main interface so I don't use the MBox that much.
As far as other options, there's tons! I'd recommend the 002 rack if you can afford it, or the MOTU 828II if you want to use something other then Pro Tools. Of course all of this depends on what kind of computer you have, whatever you do don't buy anything until you know that it will work with your computer. Do some research, figure out what hardware/ software you want to use and then make sure it's compatible. Good luck!
