I typed up another response, then reconsidered it. As to what tuner will suffice for setting up a guitar, I guess that depends. I can tell you that there is, to me, a real and audible difference in the accuracy achievable with a true strobe tuner (not just one with a strobe-type display) than with your standard needle type. I have a nice Korg Orchestral Tuner (about $100; I use it with bowed strings and my electric bass, has a real needle, which I prefer) and have played through various tuning pedals at jams, etc. With both of the aforementioned, when the tuner says my strings are right on, I can hear that they're still just a little off, and tweak by ear. With the Turbo Tuner (I've used both the pedal and non-pedal versions, and got the pedal for my younger brother), which gives you real strobe accuracy, when it says the strings are right on, there's nothing left to tweak; they're RIGHT ON. For that reason, if I were getting a tuner specifically with the intent of using it to set up instruments, I'd get one of those (the non-pedal version, which allows more customizing of temperaments).
I don't have absolute pitch, but I have good relative pitch. I typically get one reference pitch (either aurally, as in getting an "A" from the keyboard, or from a tuner pedal) and tune the other strings relative to that.
The headstock tuners that I've tried have been okay for getting close, but I've not been too impressed with them, and wouldn't use one to intonate an instrument.
Turbo Tuner:
Strobe Tuners by Sonic Research - Turbo Tuner Home Page
My Korg (
Invalid Link Removed -- $30 less than I paid for it!)