I'm in a similar boat as you so I'll follow this thread w/ interest. (hobbyist, possible small gigs in future, nothing grandiose).
I saw a used GK RB400 III (just today, in fact) at a darn good price, and after reading a bunch of + reviews will try to test it out this Saturday. A Hartke 3500 was one I tried and liked, but it wasn't quite "I gotta have". SWR 350 & 350x ... a friend of mine loves his SWR stuff & they seem to have a pretty good rep here at TB, but these 2 particular models must've been the black sheep of the SWR family.
You're probably going to get a lot of fine suggestions here from some very knowledgeable folks (present company excluded, of course), but all I can say is to just try & play through as many as you can before you decide. There are some stark differences, and if you're just starting to develop a "sound" preference, some will be hits and others will be misses.
The problem I'm coming across is I keep playing some nicer stuff, and then the "starter" units fall short by comparison. As of now, my 2 faves are a Traynor YBA200-2 tube amp and a TecAmp Puma 500 (Ken, I hate you!

). Both more than I'll ever need; just have to decide if I'm an enough of an avid hobbyist to up my budget. Good luck!