I put speakers, and I'd say don't shoot for the budget market, I'd be looking for some good mid-priced (~$500? +/- $50/pr), solid performing bookshelf speakers, since the VT-12 is already a budget minded system.
A nice looking sub is a good thing, but I don't really spend any time looking at my sub; I actually don't WANT to see my sub, just hear and feel it. I want all of the cost to be in the performance, not the appearance. The availability of nice finishes would be worth while sales wise, IMO, I just won't be one of those people who'll be buying a sub based on finish. Same thing with size - I don't have a problem with a larger sub if it gives me the performance I'm after (within reason).
PEQ would be nice also, but not if it ends up adding considerable cost to the subs.