I picked up an inexpensive 4-jaw with no backplate for mine, and have been quite pleased with it. My rotab is a 10" and I use an 8" chuck. Independent jaws mean I can dial in odd parts (which is usually what I need when I drag out the rotab). I have a ER40 collet chuck that I *could* use, but never have.
As a last note: I use my rotary table pretty infrequently. If you're just getting tooled up, take a good, hard, look at what you want to do (and think about alternate ways to do them). In my case a rotary table is way down the list of tooling priorities.
GsT