The lighted 60-100x pocket scope from radio shack is the best for checking trichs. It's about $10 and my only complaint is I wish I would have looked for one with an LED. If you just want a closer look at your babies any magnifying glass will do.
I like the 30x joulers loupe, like the first one that Roseman posted, for looking at my girls when they are in the room,, sort of 'on the fly'.. if I want a good close look, I snip a small leaf off, and sit down with the ratshack one.. I just cannot stand at the plant with that ratshack microscope and actually focus in on anything
although I did see a wireless, USB, microscope on thinkgeek,, it was 90 bucks though...