Well, I had a similar problem with a low ceiling height. What I installed is a product called Ceiling Max. This is basically a suspended ceiling that attaches directly to the joist so zero loss of headroom. It's a bit more expensive than your standard suspended ceilings but I found it was worth the extra cash to maintain accessibility. It can be found at Home Depot and you'll need a helper to install it easier. I then installed the Armstrong 2x2' Brighton model tiles. Here's a link that'll tell you all about it
http://www.acpideas.com/index.cfm?li...ar=00005.00013
Just my opinion, but this was way better than installing drywall cause I could cut the holes easier and not have to do any upside down mudding and sanding
Here's a couple of pics to show you what it can look like:
