Midway's Wheeler is the bargain of the age. I have one that I paid full freight for and don't feel slighted. I may order another!
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=577167It's a little less sophisticated version of that nifty red guitarmaker's vise. At $47 and change, you can't go wrong.
The first thing I did when I got mine was to remove the wood jaws and make some extras out of shop scraps--some maple, some cherry--and faced a couple of pairs of spares with heavy leather. I've thought of making a pair of steel ones as well--maybe when I get that spare vise. You could make some of different lengths and contours as well.
I make custom furniture for a living, and vises and clamps are a big part of my working day. I had no idea how much I'd come to use my Wheeler. I doesn't do everything I need in a vise, but that's what my traditional bench and vises do. When I need it, it drops in a bench dog hole in my bench in half a minute. For the money, it'd be my first choice if thinking about building a gun or two or three..