Hey man, bass heads are awesome for guitar (or atleast for what I play). It gives you great bass response and depending on your cab and what kind of effects you are running you can still keep your mids and highs.
In my opinion go either with an ampeg or gallien krueger, ampeg would do a bit better. I'm running a gallien krueger 400RB and it sounds awesome.
If you've got the effects then dont worry about finding a bass head with alot of preamp gain. The VT-22 is awesome, a fellow guitargeek turned me onto it, I had the pleasure of jamming on one rescently, however if you've got the overdrives/distortions and other fx then the preamp gain is a bit overkill. either get a strait up clean bass head and run the fx, or get a bass head with tons of gain...but to run both together (in my opinion) will kill your tone.