I'm the guitarist in our band but my bassist is looking for a proper bass amp that will be better than his starter one.

We are like a Speed/Thrash Metal band, heavily influenced by Megadeth, but also stuff like Sabbath, Maiden, Metallica, that sort of thing.

This amp should be loud enough to play gigs with, cause we've been doing some recently at schools and things, and we've just been borrowing the school's bass amp for that. So what can you guys reccomend me?
Godammit smb, you reduced my answer to a mere +1.

Ibanez SR506BM
Ashdown Little Giant 1000w
Peavey TVX 115+410
A big ass upright