In OldWolfs first post he recommended a single light and a soft box. That is a really smart way to start. A good monolight, decent stand and a med or large softbox and you will be set for a while. Buying a decent monobock means you never have to say your sorry
. A brand name unit will be easy to sell if you decide its too much. Starting out by buying a good unit will also be the foundation of a larger set up should the bug grab you and not let go.
Alienbees, Photoflex, Calumet all offer single light kits. You will need a way to sync the flashes: optical, wired or radio.