Me again. I'm pondering getting a SB-600 flash unit for my D50. Am I right that I might benefit from a diffuser, since right now I'm doing a lot of portraits, baby- and maternity shots? I keep putting off the decision to get a faster lens and for some reason I keep telling myself maybe I can get away by buying a flash first to compensate for the speed issue. Now that I read my own words I know it sounds completely weird. Gosh, somebody please drop $800.- on me, right now. Anyways. Diffuser - yes or no? Plastic or fabric? Decaf or regular?