Setting up a 33 gallon cube - looking for ideas!

[fishymommy]

Well, I've thrown in the saltwater towel.  I'm pregnant with #3 and I'm just tired of mixing R/O water, I guess.  I want the ease of my Python back!  

So I'm looking for ideas for my cube!  I'm keeping the 175w metal halide pendant I have, which currently has a 14k bulb in it.  I can/will switch that eventually, to a lower K, but for now, it'll just have to do.  I just bought the bulb a few months ago and at $60, I don't care enough to go buy a new one just yet.  For filtration, I have a Penguin 350, that should do fine, dontcha think?  

I'm thinking of putting in some low light plants, driftwood, maybe a holey rock or two.  I'm really interested in the freshwater gobies, except not the dragon one, or anything that needs brackish water.  Peacock gobies maybe.  Anything else like those that I can look into?  Have you guys seen these at any of the LFS?  

I also really like German blue & gold rams, so maybe a mix of those.  And maybe a couple of Boesemani Rainbows?  I love FW inverts too, I'd like to have a bunch of blue or red shrimps in there.  

any other suggestions?  Substrate suggestions?  I think I read somewhere once, but maybe I dreamed it, that you can use potting soil in aquariums for planted tanks.  Is that crazy or would it work?  Has anyone done anything like that?  

Thanks!
Annette