For most small to medium size work that needs to be held in a vice I use a toolmakers vice of this style -

http://www.flexbar.com/shop/pc/catal...Image_0002.jpg

which pulls the moving jaw down and closed at the same time, mine is around 250mm long.

After messing around for some time with cheap new, then what I could find half-decent second hand I finally spent £120 on a new Vertex Toolmakers vice and dixcovered the difference that a good vice makes, for me money thrown at a good vice was money well spent,

- Nick