No budget limits? No particular style or sound to shoot for?
If you already like Mesa, the 5.25 Express is worth a long look.
Vintage Fenders are really nice (real ones, not the reissue things), but they cost more now than ever before if they are mint. Champ, Super Champ, Princeton is an awesome amp. I will stick my neck out an dsay the new Super Champ XD is awesome sound IF you switch the tubes and the speaker, or plug into a 12 or 15 inch cab. Or for real bang for the buck on Fender clones, check out Frenzel Tube Amps. That guy REALLY knows his stuff, great prices, and superb service, well worth the wait.
Traynor is always a good bet for a part time amp, YCV20WR is a nice little beast, always regret selling mine. They have a hand wired little bugger, I think it's a YGM-3. The Tiny Terror is 15 watts, nothing tiny about the sound. On a budget you can try
the Carvin Vintage 16. Some people swear by them and love them, others love them but have occasional repair issues, good service from the company though.
If you are really on a tighter budget than those, then you may be stuck with whatever fluke of luck you can conjure up at your local GC. (Sorry if that's the case, imo GC should be the last place you go to buy something......but not all GC's are created equal, I will admit!) If your budget is looser than that, then you can start looking at THD Univalve or Flexi 50, some small Laneys, used Budda, used Orange, mint used Ampegs are always nice to find, or you could build your own. Modded pedals will make a difference if you go for something more than just great cleans. Let me put it this way.......if they sell it at GC, put it at the bottom of the list and do your research on the other brands first. If you absolutely cant afford the others, then do your home work and test driving at GC several times before you buy.
And don't discount the effect that pickups have on your tone. That's the first place that sound gets translated from the strings to an electric signal, so your final tone can only be as good as what comes out of your pickups.