i highly recommend the hughes and kettner cream machine which is a 2 valve amp (power and preamp), with an extra opamp booster on the input.
search ebay for one. it has 1watt of power which is more than loud enough in a flat (a bit too loud).
metal is no problem - it has plenty of overdrive to spare, i know - i have one ;) even with the preamp changed for a 12at7 it has easily enough drive for hardcore experimental grind. with the gain on the minimum setting, it has a "bluesy breakup". you have to roll back the volume on your axe for a real clean.
i describe it as "vintage hi-gain". for a more modern metal sound, you might want to pair it with an eq pedal.