[quote name='FinnDave' timestamp='1484489399' post='3215818']
Our guitarist uses a 20 watt valve combo and can still drown out the bass (and drums!). Maybe 15 watts is a sensible max for guitars?
[/quote]
I play with two guitarists, in two different bands. The first one had a VOX AC30 which was insanely loud and incredibly heavy. The second one had a Fender Deville 410 combo, which was (yes you guessed it) insanely loud and incredibly heavy.
They have 'seen the light' and both have got themselves a, 15 watt, Blues Junior. They are more than able to keep up with a loud drummer, sound great and won't give themselves a hernia.
If they play bigger venues they can just mic themselves up through the PA.
I'm happy, they're happy, everybody's happy. It's the way to go.