There is no magic number, and it really depends on your specific set of software that you want to run. So don't fall into the mental trap of thinking it has to be X or fewer, because for you 90 might be perfectly normal, but for someone else 70 is the sweet spot. Another mental trap a lot of people fall into is obsessing over performance. If things are running well enough for you, don't worry about it, spend time enjoying the computer. Make sure to stop and smell the roses so to speak.
On startup my computer is running 90 processes and I was told that anything above 70 is usually to much.
The only start up programs I have along with the OS (Windows 7 64-bit) are:
This computer is a laptop. HP DV7