<A drum set is one instrument, not a bunch of individual instruments.>>
i totally disagree. IMO, a drumset is indeed a bunch of individual instruments that work as one whole (hence "set of drums"). it's analagous to a trumpet section. they all need to work together, otherwise, you've got a collection of individual slop. that's what makes recording drums so difficult--it's like recording a brass section or a choir, and everyone needs to be in tune and evenly balanced to start with--lest ye be sunk from the start.
i DO agree that while drums have a single "fundamental" pitch they sound best tuned to, they do have a range in which they "sound just fine" at. i've always tuned my drums a 3rd apart, so when you hit a couple toms at once, you get a musical chord, rather than a random cacophony of drum sounds. this takes a bit of an ear and it helps that i play guitar and keys. tuning drums a 3rd apart often means that they're not exactly at that fundamental pitch, but rather in "that range".
FWIW, DW has a service (or line of drums?) where they'll put together a set of drums that have been pre-selected to work together. i've always found this intriguing, but not worth the money to me (whereas it would be to someone who plays drums regularly).
no, a drum dial will NOT tune the drum for you and it will not take it to a specific pitch. it is IMPERATIVE that you know how to tune the drum correctly in the first place before even using a drum dial. all the drum dial will do is help you do is *fine-tune* the drum once you've already gotten it there--all the drum dial does is gives you a readout of the head tension (at all of the lugs or wherever you place it). this goes a LONG way towards eliminating those nasty overtones that people have always used duct tape, toilet paper, moongel, etc., to compensate for.
but in a nutshell, you have to learn to properly tune drums to begin with. and a well-tuned drumset will go miles towards improving your drum recordings.
cheers,
wade