Hi, A lot of my general purpose bits are Freud. They're hard to beat. They make specialty bits as well. But for door making sets, I have and really like using Sommerfeld Tools matched bit sets. Matched sets have the shank milled to exactly the same length, so you can set the first bit in the set, then switch to the other bits without changing router height.
I also like watching the late Marc Sommerfeld's videos (on youtube). He was a cabinet maker before starting his router supply business, and his technique is simple and elegant. Some of the best videos out there because he doesn't cut away to keep it short, so you see the entire process. He uses his own products, but isn't promoting them so the videos are really good.
His company and many others produce annual catalogs that are great to have when you're looking for a special profile. Most of the bit suppliers offer them.
Finally, for door sets (good for more than doors), Sommerfeld has a great little accessory called the Easy Set, a kind of star wheel that makes setting bits really easy. Unlike standard blocks, these adjust for the thickness of the wood you're using. It comes in yellow for Sommerfeld bits, and red for the same bits from Freud. Not very expensive either.
