#1
I’m looking for a combo tube amp, possibly a stack depending on the price.
Needs to be good for high-gain metal, and loud enough for small gigs.
My budget is around $1000-$2000 Australian Dollars

kgo.
RIG
Guitars:
Fender American Strat
Carvin Bolt
Aria Fa 71
Epiphone Les Paul
Yamaha FG700S

Amps:
Hughes and Kettner Trilogy Half Stack
Marshall MG *hides*

Pedals:
Dunlop Crybaby
#2
If you can get it in Australia, I suggest Carvin's V3 halfstack or 2x12 combo. Great for everything from sparkling cleans to flesh-rending metal. Great tone and build quality. Blackstar has released the Series One 40-watt (or is it 45 watts?) combo, which is supposed to be a first-rate amp. If you are willing to go used, look at Marshall and Mesa combos.
#3
If you want to stick with the low end of your budget, Peavey Valvekings are great for everything except the most searing of metal, but that can even be pulled out of them with the right pickups. You can get a combo, or even a halfstack or fullstack well in your budget. I have tried them on many occasions, and belive me, you can get pretty much any tone out of this amp that you could think of. If you search Peavey valveking on youtube, there are like 700thousand vids of people doing metal with it. A guy on there named Braddy Vengance has a bunch of cover vids of him doing things like Killswitch Engage and other metal bands and he gets a great tone out of it.