50 watts into a 1x12 or 2x12 cabinet would give you plenty of clean headroom, and if you need to push it harder, but without the volume, you can always get an attenuator, like a THD Hotplate.

My amps are all in the 50-60 watt range, and I have no problems getting great tone at "basement jamming" levels.

The speaker you use will also play a big roll in how loud, and how hard you can push the amp.