I like to use ratcheting clamps that I got at Menard's (and I'm sure Home Depot carries them too). They come in different sizes. I found them in the aisle along with other types of clamps. Don't have a photo of mine, but they are somewhat similar to these:
http://www.amazon.com/Bessey-XCRU5-R...dp/B0012YOC2K/
The ratchet makes it very easy to tighten and loosen in small increments. The depth allows for a deep table. Mine are made of plastic and the plastic grips are gentle on the table; plus the ratcheting allows me to tighten just enough and not too much.