I'm embarking on purchasing my first "big amp". I play a small practice amp now and I'm looking to move on to something semi-permanent. I want to play Sabbath/Maiden/Zeppelin style, mostly classic rock/blues with a pinch of metal. And I want it to be gig worthy.. at least small gig like 100-200 people.

Does this sound adequate and/or worth the money?

"Yeah no problem sounds good. I purchased it in 1997, only played it a
few times in band practices and started to get more into solo music
recording and composition on the computer, so I have not used it very
much at all. Anyway the tubes have barely been used it has an outlet
for a footswitch to switch between 2 different volume channels, one
channel for solos and the other for rythm. I did not by it with the
footswitch and I never purchased one. I usually just used my effects
unit anyhow. Its a 50 watt head, so bare that in mind. It gets
really good volume, but I remember playing with a friend who had a 150
watt and getting a little over powered. Its in really good condition
overall except for a few tiny nicks on the cab."

Is it powerful enough?

Thanks dudes.
It will be powerful enough unless you're going to try to get jazz cleans out of it over a drummer. What kind of amp is it?
Oh yeah, I guess I didn't mention that.

Its a Marshall JCM 900. I want a Marshall amp, but is 50 W powerful enough? I will only be playing a rock/blues style. I play on my friends Fender amp now (not sure how powerful) and I'm not satisfied at all with the clarity of the solos, its just too fuzzy.