If all you are doing is using it at home, a 50 watter will probably be way more than you need. One thing to consider about tube amps is that for them to really sound good, the tubes need to have juice cranking through them. And 50 tube watts is actually pretty damn loud for say, your living room.
One thing to look for, if you are set on getting one about that powerful, is a master volume control. This allows you to saturate the tubes by turning up the master volume, but keeping the output volume low so as not to scare or enrage the neighbors.
The Traynor Custom Valve series is an excellent alternative to Fender amps. IMHO, the "dirty" channel on the Traynors is much more useful than on Fenders, and the Traynors are much better built. The YCV40 is a 40 watter, and there is a 20 watt version that is actually more suited to living room use. The Peavey Classic 30 is a nice amp that doesn't get the respect it deserves. Another thing you may want to consider is going on ebay and looking at older Fender Princetons or Champs - nice, smaller tube amps that sound great, and aren't too expensive, usually. Lots of them out there.
Yes, I personally think tube amps are worth it. After all, what is everyone trying to emulate with all the modelers out there? However, they are not as versatile as the newer modeling amps, not by a long shot. So it's a trade off. Do you want a one or two trick pony that does the tricks very, very well, or a pony that does evry trick in the book, but none of them as well as the two tricks the other pony does?
Out of the loop? I didn't know there was a loop!