I /severely/ reccomend a Yashica Dental Eye (I have a III. I got one a year or so ago for $50 from a dentist, hadn't been used more than a few times. Has an amazing 100mm f4 lens with ringflash; 2 or all 3 elements (or none) possible to fire for various effect. You can get them on ebay $75-150; they come in a real cool case, too.
Only drawback is the thing's pretty automatic (not focus of course!); only adjustments possible are +- 2 stop exposure; the shutter and aperture are auto. Fixed lens. Plus film speed is DX only. But with the high light you get a pretty good DOF, plus a real interesting 'chromium' relief look that has to be seen to be appreciated. (I shoot stuff like leaves, mosses, plant parts with this).
Farthest focus is about 2m - there's youtr infinity for macro! I think it might make a decent portrait lens, actually (flash off!).
I don't feel the need for any other ringflash setup with this; it's perfect for me.