I second the calls for a nicer, possibly even old and beat microscope, as long as the lenses are good. I have an old Olympus KHC microscope I got very cheap. The lenses are good quality and everything is very clear.
It is really fun to be able to see what you are putting into your beer, and it gives you confidence that what you are doing is working, for example when you are trying to start yeast out of a Rogue bottle and you cant tell whether those bastards are going or not...
Both methylene blue and trypan blue are good live/dead stains for yeast. Both are cheap, the former probably more so. You could also pick up a microbiology protocol book (Uni library's a good place) to learn different stains and techniques. For example, if you know you've either got acetobacter or lactobaccilus, you can do a gram stain to tell the difference between these two. Easy and cheap. Microbiology is fun, even if it does push the geek boundary at home. (I do this stuff at work too, so take that for what it's worth...)
Also good investments are a hemocytometer for counting cells (eBay is your best bet: $15-40)--they have special, thick coverslips, so make sure either the hemocytometer comes with some or you get some elsewhere. One more thing, sterile, wrapped, plastic Pasteur pipettes are a FANTASTIC thing to have, when you want to take a sample of your yeast starter and not contaminate it, or when you want to take a sample of your wort without having to sterilize the pipette first, etc etc etc