Probably the best gunsmith vise currently on the market is the "Multi-Vise".
http://www.brownells.com/aspx/ns/store/ProductDetail.aspx?p=361&title=MULTI-VISE?
This is the most flexible in the number of ways it can be positioned.
It's expensive, but about as good as it gets.
One thing you don't want to cheat on is your vise. Ordinary Sears or shop vises just don't cut it for professional use.
In addition to my main vise, I also had a small swivel jeweler's vise, a jeweler's size Wilton vise (now discontinued??), and a huge Wilton that weighted about 100 pounds.
For revolver barreling work I had a small Wilton vise with modified jaws for holding barrel blocks.
Although I seldom used it, I had an engravers ball, which is a heavy chrome plated steel ball with a "universal" vise in the top, ball bearings in the middle which allow the top to rotate, and a heavy leather "donut" ring to rest it in.
One of my colleagues who did a lot of hand filing made his own vise with hydraulic "fingers" to hold things.
One of the better vise jaw pads are the elastomer plastic versions. This grip very well without any slipping.
http://www.brownells.com/aspx/ns/st...x?p=22186&title=ELASTOMER+PAD+FOR+MULTI-VISE?
I have a few pieces of a blue plastic that was reportedly developed to line missile silos that I still use.
This is a odd synthetic that's hard, yet can be bent easily and allows parts to "embed" into the surface holding them very firmly, without scarring.
When the parts are removed, over a period of hours or days, the impression in the material fills back out.
I suspect the above inserts are made from the same stuff.