We own a nice Bridgeport mill equipped with a DRO and what technically qualifies as a metal lathe.
I run the mill almost exclusively. I made pretty much every single machined part on our robot this year excepting the hex axles (which were done in the lathe). It can cut things to within 0.001" of the size you want it to be, provided care is taken and a competent person is running the machine. It can also drill holes in the location you want them to within 0.001".
To my team the mill is far more valuable than the lathe, because the lathe is a really bad one that breaks easily. Generally though, a lathe is very good for spacers and modifications to anything that goes on a shaft. A CNC mill can do a great many things. Getting a nice CAM program for your CAD program could be useful, depending on the situation.
We use the drill press and bandsaw to make gussets for riveting things together on our chassis. Just bandsaw to the right profile, sand it all to make it look nice, and then we drill the holes in the right locations.
We use a chop saw to cut aluminum. It functions somewhat like a cold saw. I believe there are cold saw blades with the right tooth geometry sold for cutting aluminum, but generally a horizontal bandsaw will do you just as well.
Surface grinders are for making surfaces in steel shiny and flat. They can also grind something down accurately to within 0.0001" height. Steel is far less common than aluminum in FRC (for machined parts, at least) so I doubt you'll ever find a use for a surface grinder, unless you want to make jigs or something.
If your university offers courses on machining, have new students take them. They are fantastic resources.
EDIT: Not my team, but an eample of what can be done on a CNC mill (or a manual mill if one is skilled enough):
https://lh5.googleusercontent.com/-M...480/13%2B-%2B1