You're talking about MySQL right?
It will depend on the hardware that you are running, and the load generated on the server and how many visits are actually hitting the database.
For us, on our Quad Core Xeons with 4GB ram we run 100 as a standard and then increase with more ram. Again, it's relative to the usage on the machine too. I've never seen it set at 10 before though, that's awfully low. You'll find SOME hosts even set this up in the 500 range, but again it depends on your hardware and what you're doing.