It would depend on your purpose. If you want sauce, then the plum types (i.e. roma) are recommended. If you want whole or chopped, then the medium sized ones (rutgers comes to mind). The "big, juicy type" (beefsteak, delicious, whopper) will work, but will also produce a lot of "juice".
When I can, I prefer them whole or cut in half. The big ones are usually cut in quarters. I like rutgers, celebrity (a little larger variety), carmello, dona, and homestead. Stay away from the cherry variety as they are a pain to peel.
Good luck.