#2
Try a Traynor amp. They are awesome for the money. You can pick up one on Ebay for between $250-$400 in the 20w or 40w models. I've been using a YCV40 for quite a while and it's a killer combo...40 watts with a Celection 12" speaker.
#5
A 50 watt Peavey Valveking 112 tube combo is a great amp to try. Not sure if it gets far enough into metal territory for you. $429 USD. Other than that you should look used. Some good deals on Peavey Classic 30's out there. Any amp you get at that price will need a push from a pedal for metal.