Well you got single coils which...well one coil. Bright sound, great attack, usually slightly scooped compared to the alternatives, perhaps a hint of a lovely hollowness. Killer for clean and low gain sounds. Has that distinct snap and chime we love in teles and strats.
Has to be combined with other PUs for wiring fun.
A HB essentially is two SCs wired together to cut out the hum, though other frequencies are also cut in the process. Also the coils are not wound as much as a single coil pu, since you got two, so spliting one is not like a SC. You get more output, weight and mids, usually more creamy too. Sound is much bigger and fuller than with SCs and also rounder and smoother.
Can be split and coils can be turned out of phase with each other and can be switched around from series to parallel wiring. That is with the correct wiring.
The P90s is a true single coil, but uber fat in wind, magnet and coil. That gives you the full frequency response, attack and chime of a single coil and the fattness and power of a humbucker. You also get a very distinct midrange roar and agression. P90s can scream and sing depending on what you want. Also best PU type to handle fuzz.
Wiring options like with the SC.
This is just a general idea though, there of course is more to it. The Bellamy sound to me is a lot about using fuzz though (P90s rule) and about that pick attack of SC while being fat. You just hear that he uses them a lot.
