Mr Ransom,
I suggest you don't bother changing the pitch of your drums unless they actually sound wrong.
Even if they are 'out of tune' it might still sound cool. Sometimes I deliberately make my percussion out of tune so that the music sounds a bit more sinister.
In theory there are two types of percussion, tuned percussion (e.g. bongos) and un-tuned percussion (e.g. snares). In reality, I don't think there's any dividing line - some sounds have more 'tuned' content than others. I guess it depends on how much of the 'primary' frequency you can hear, and how loud the harmonics are - but I'm not a physics expect
Most synthesized kick drums do not sound tuned, because they rapidly change in pitch at the start of the note and continue to fall in pitch more subtley as it fades away. However they sometimes sound more tuned because they settle on a single, low pitch. It just depends how the artist has 'designed' the sound.
Also remember that the human ear is not very good at deciphering lower frequencies - so we might not be able to differentiate a tuned and a more 'un-tuned' kick. If you apply distortion to the kick (e.g. as they did in hardcore records) the difference is more obvious, because there is more treble content in the sound.
For a very percussive sound, check out my own tune:
Perilous It's fairly dark progressive house / techno.
Later mate
Bongo Fiend