Re: Cabinet help
I'm going to say Avatar, simply because I have experience with them and I know they sound great.
Some people are going to chime in and say Buzzbomb - based on my experience with ported cabinets in the past, I'm going to advise against them. The bass was always extremely flabby, nowhere near what you'd need to be playing any sort of metal.
That said, what style of music are we talking here?
Also, you might want to keep in mind that I don't like Mesa cabinets, so my advice might be totally different than what you're looking for. I find them way too boomy, and very hi-fi... kind of a dark/shrill at the same time type of thing.
My ultimate suggestion would be an Orange cabinet, but that'd run you more than the Mesa, and they're heavy has hell - made of 18ply birch.