I'm in the basement too. I couldn't put in a ceiling due to all sorts of random obstructions (water pipes, phones lines, you name it) in the way. The ceiling is exposed joists and the subfloor from above, and not too clean as you look at it. I thought I'd try it without anything to see if it would work and so far it's great. I don't vacuum as Art suggests, and I haven't had any real dust problems. I do take my neg's upstairs to hang in the bathroom though, so I don't push my luck!

I'm not sure I'd really recommend a suspended ceiling though, at least not the types I see in most commercial work. They are made of mineral fiber for the most part, and they tend to get friable in time. Taking them in and out is a messy task (in darkroom levels anyway) even with new tiles.