Though I don't care much for their live performance sound at higher volumes, it would be tough to go wrong with a modelling amp just for practice. You can get some pretty convincing tones at fairly low volumes (and most if not all come with a headphone jack), can dial in some pretty accurate simulations of recorded tones (with the advice of some of the instructors in the "Songs" section). Best of all, they are relatively inexpensive (especially used), quite reliable, and some even record fairly well.