I've played all the amps, and all of them sound good, alot of companies make quality bass amp products, Ampeg, Markbass, Eden, Ect, but StingRay's sound best through Gallien-Krueger, thats just my opinion.
Go to RMCAudio.com, they have the best prices on GK stuff, and great customer service
Gallien-Krueger and Trace Elliot for me.
I use a GK and have never had a problem with it, but as soon as it dies i'm gonna get me a Mark Bass, very good amp.
I've owned and gigged with all of the amps listed in the first post.
My first real amp was a trace elliot. really good, clean sound. I sold this and went with a GK800RB. really powerful, gutsy, growly, ballsy amp. Sold that after a few years and bought a Hartke HA5500. Good variation in sound, compessor in it wasn't very good - overall a really good amp. I then went with an Ashdown EVO something or other, the chrome rack mount one. Far too boomy sounding for me. I was never happy with the sound.
I have since got myself a 700RB II and couldn't be happier. Good aggresive tone but it can be tamed if its too in your face for certain songs, bucketloads of power and the valve emulator is really good as well. I wouldn't hesitate to get another if it stopped working.
Just stay away from Hartke when I started to play bass a little over a year ago I did not want to spend too much money on bass amp so I bought Hartke amp head and within a year everything fell apart I bought Ampeg B2RE later and it is well built and dependable amp and now I know that trying to save a couple hundred dollars on equipment and you actually end up wasting your money