If you really want a nice meter, get a fluke. they have tons of add ons you can get for them, but they're outrageously expensive... personally I'd recommend finding one with auto-ranging, recording and data hold.
auto-ranging means not having to pick between Mohms, Kohms, or kV, V, etc. (except maybe mV or uV) you just pick the ohms or volts setting and it'll display what the range is.
recording can be infinitely helpful, connect your meter, hit record and pick min or max and as you go through hitting points it will hold the highest or lowest reading that you come across, find a higher one? well that's the new reading it will display, so it changes as you find higher or lower points than the last one displayed.
datahold is helpful sometimes, basically I like to use it so I don't forget voltages or ohm readings. take your reading and while it's still displayed on screen hit data-h and it keeps that reading up on the displayeven if you remove the probes from what you're working on...
other than that I'd say a wide range of functions (Amps, Volts, Ohms, diode tester, continuity tester, AC/DC) is the best thing to look for. Oh, yeah, and an auto off feature is really nice too, that way you don't kill your batteries...
this is the meter I got went I went to mechanics school, it's labeled "blue point" (which is the 'low end' snap-on branding) but it's actually a basic auto-ranging Fluke meter that's just re-branded for snap-on. I was required to have one before starting school and this was the one they were selling and it was actually comparably priced at $100 (it was actually about $20 cheaper than the fluke version at the time)
the range button turns off auto-ranging and lets me select the range if I want to...
