For many years, guitar manufacturers were divided into two distinct camps with Fender favouring single coils and Gibson preferring humbuckers. But the advent of the superstrat, favoured by heavy rock players, opened up the possibility of combining single coils and humbuckers in various ways. As mentioned previously, the most popular combinations are S-S-H (single coil pickups at the neck and middle positions, humbucker at the bridge) and H-S-H (humbuckers at the neck and bridge with a single coil between them). The latter is possibly the more versatile combination.
The following diagrams represent standard ways of wiring tried and tested pickup combinations. Of course, there are many more possibilities, especially with coil splitting and phase switching thrown into the mix. If you want to explore this yourself, there is no substitute for acquiring a little basic electronics knowledge so you can experiment confidently. All the major pickup manufacturers provide comprehensive wiring information, both with their products and on the web.