Help build me a new rig!

[JimBobTTD]

It's Sunday...things are slow. As a product of the modern world, my thoughts go to acquiring more gear in an effort to stave off the emptiness inside me. Sort of.

My dilemma:

I have a GK 400RB (180W at 8, 280W at 4 ohms), which I like very much and it has served me very well.
I have a Marshall 1x15 (unoriginal speaker) which I do not like all that much. It's ok, but it doesn't make my GK sound as good as the Trace cabs I once had. It seems to lack something, but I can't put my finger on what exactly.

I have a new metal band in the pipeline. I'll be competing with two (probably half-) stacks. Is what I have going to be enough? I'm looking for defined bottom end with some GK growl. I use EMGs in 5-string basses and a compressor. We will end up playing smallish clubs and rehearsal places.

Thoughts? If the 400RB is not powerful enough I could consider upgrading to the 700RB, but I would like to stay with GK. As for cabs, I'm really rather open to all suggestions at any price point. Cheaper the better, obviously, but I would rather have something good and solid than cheap and nasty.