I use a Roland KC-300. The current model is
the KC-350.
http://rolandus.com/products/productdetails.aspx?ObjectId=583&ParentId=33
The 350's are built really tough, sound great, and are still quite compact. They have a lot of features that are great for keyboard players, like four sets of stereo inputs, built in eq, a mic input, RCA inputs, headphone out, subwoofer out.
My KC-300 has most of those features, but I think Roland improved it with the 350.
Roland makes a series of keyboard amps.
The KC-550 is huge and heavy and would probably be a bit much for what you are describing.
The KC-150 might not have quite enough power, although it's possible it could work for you.
These Roland amps are by far the most commonly used by keyboard players, at least from what I've seen on gigs.
Another line of amps that is supposed to be good (although I've not used one myself) is made by Barbetta. Like the Sona-31 or Sona-41. These would be seriously loud if you need that.
http://www.barbetta.com/html/Live/live.html