The 10 essentials. Made by whiteside. IMHO, hard to do better for the same money.
A similar set by Bosch. I like bosch bits too, but not as much as whiteside.
A very nice set by freud. Also excellent bits.
Another whiteside set. Less bits, but cheaper.
A set by CMT. I like their bits as much as whitesides.
I've used all of these brands extensively; the routers in my shop are my absolute favorite and most used tools.