Well I'm not sure about single speaker units that I have had experience with but I can give you a whole list of combo amps with two speakers that are great.
What is your price range?
Just about any midrange Fender amp is versatile,
pretty much depends on the music I'm really into blues so small Fender amps are of course the choice picks for me. I have also had alot of luck with a Mesa Heartbreaker great little amp for tracking. You pretty much have to just go to the music store and decide for yourself. Vox makes great amps also.