I have a microscope - in fact I have two - and DS was the excuse. Can I help? I am no expert, but I did a lot of reading around before buying. I'm afraid I'm not sure about seeing cells divide and replicate: that's pretty hard to achieve outside a serious lab, I think, though I'm not saying it's impossible. What I got first was a good stereo microscope with a zoom, the kind sold to schools. This is good for looking at whole specimens (pieces of leaf, insects, twigs, hairs, needles...) rather than things having to be prepared on slides (though we do look at things on slides too). I do also have a compound microscope, with higher magnification, but that actually isn't so much fun at this point. Here's one site that may be useful - there are lots of others of course:
http://www.brunelmicroscopes.co.uk/microscope-facts.html

Key message from everyone seems to be: avoid anything which is a toy; don't worry too much about magnification, quality of optics is far more important.

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