In reply to Tony T: I can only think of a handful of routes that rely purely on leader placed pegs. They are usually very very scary. There are some scary ones that need pegs, but you'd be crazy not to take clean gear too (a leader placed peg when free climbing is no mean feat). Occaisionally there are non scary but adventurous routes that need pegs, they are usually in remote areas.
If you are not just winding up the more parochial brits, where are you getting all these pegs from, and can I get some?