What are the features on a microscope one needs in order to do lab work?
It sounds like you need a microscope for standard microbiology lab tests. At a minimum, any standard wide-field/brightfield microscope would work. If most of your histology work involves colorimetric stains (e.g., H&amp;E, gram staining), you don't need any fluorescence capability. If you are working with a lower budget, look at the new lines of LED-based miroscopes, which dramatically drop the cost (I think around $10,000).

If you plan on doing a high volume, in particular of fixed histology/cytology slides, then you may want to invest in some of the automated slide scanner microscopes. They have a small benchtop footprint and can be programmed to image large areas automatically, for later analysis.