I would personally go with a veneer over MDF. There are several reasons for this.
1) Much larger range of choices (I see you pretty much looked at the generic woods)
2) Cheaper
3) Easier to make (hardwoods, especially over a specific gravity of 1.0, are a bitch to cut! And when you have to miter fold, it makes that 45 degree a challenge)
4) Less tendency to shrink/swell with moisture changes
If it were me, I would go with something that is really going to impress people. Go with a highly figured veneer. I have always been partial to Brazilian Rosewood ($5-$9/sq foot) , but you have to bleed it first. The extreme grain contrast are awsome. A little more subtle approach would be Paduak ($0.85 sq ft) or a mottled Makore ($1.75 sq ft).
I always use certainly wood to buy veneer. They have ridiculously nice wood, and thier specials are unbeatable.
http://www.certainlywood.com/sales.cfm You have to buy at least 50 sq feet though.
This is the job that made me love Rosewood. It would look amazing on a set of towers.