ooh, a mesa rectifier... my favorite! they are really good rock/metal amps, so if that's what you play, they are great! marshall DSL and TSL amps are in my top 5 favorite amps too, they are a little less "hard-core" then the mesa, but can pull off every tone that I want out of it.

if you ARE going for the rock/metal sound, in addition to those amps, you should check out the Marshall Mode Four, and the B-52 AT-100 amps.

if you AREN'T going for the rock/metal sound, the marshall DSL would be your best bet as it's very versatile. actually most of the amps I mentioned are very versatile, but the mesa, B-52, and Marshall mode four really are more designed for a high-gain sound.