what are the best guitar maintenance/cleaning kits for acoustic guitars, and for electric guitars? by best i mean highest quality and most extensive
I've had good experiences with the Dunlop 65 set thingy.
I'd 2nd the Formula 65 set. For fingerboards, I use Dunlop's Fingerboard 1 and 2 (prep and conditioner, respectively).
will that work for acoustics and electrics?
Well it depends, if you're acoustic has an oil finish you can't really "treat" or "polish" it in any way except steel wool, or re-sanding and re-applying the oil. But most acoustics seem to have some sort of gloss polyester/lacquer which you can use the same polishes as electrics. Fretboard oil is fretboard oil and will work for anything.
And for electrics, always keep a philips(sp?) screwdriver and an alan wrench set (if you have a floyd rose). I also agree on the dunlop 65, use that and a microfiber cloth to clean your guitar, and for the fretboard just use some lemon oil.