I just re-read and maybe you're not looking for over-the-top gain. When a lot of people around here talk about "nice distortion", they're thinking metal. Personally, I'm on the lighter, crunchier vintage side of things. I assumed you were talking about modern high-gain though. So perhaps you could clarify what style you want?
I have the Traynor YCV20WR amp and love it. The drive channel is okay (perhaps some different tubes would improve it), but the clean channel is great. With my gear (Line 6 M13 and a few homemade pedals---modified Marshall Shredmaster copy, a compressor, and an envelope filter) it can stay nice and glassy for my Egde-like delays or go to all out rock with the Shredmaster or other dists in the M13. I seriously love this amp. For reference, my previous rig was a Line 6 Vetta II I had for 5 years.
Traynor also has 40 W, 50 W, and 80 W models. Make no mistake though---my 18W gets over drums no problem. Tube power is loud, and the 12" speaker helps as well. If I were playing metal, it would probably be a different story. But for anything from blues to hard rock it does just fine. Playing live, we mic anyway, but I get all my stage volume from the amp. Now if you want to keep perfect jazz cleans and get over drums, you'd probably want the 40 W. Speaker size is a big factor too... I would not go for anything other than a 12".