Try the Canon XL2

Without knowing your audience, it's difficult to recommend one specific camera, but it's generally accepted that the Canon XL2 is the entry-level filmmaker's camcorder of choice. It's a 3CCD camcorder with excellent picture quality. Danny Boyle used the XL2 to film 28 Days Later and it's also been used in several other cinema releases. This means -- with skill -- you'll be able to get footage out of it that will impress any movie executive.

It's worth noting that unless you're a good cinematographer and have some solid actors to play the parts, dramatising your screenplay might not necessarily be the best way to pitch it. Since you're trying to demonstrate how your dialogue comes alive off the page, image quality may not be important. The studio is interested in your screenwriting skills, not your filmmaking skills. In this case, almost any recent MiniDV or hard-disk DV camcorder will capture near-broadcast quality footage when you are shooting in excellent light.

Also, at around £2,000, the XL2 might not be your idea of moderately priced. For your needs, you may find that a more lowly consumer camcorder like a JVC Everio GZ-MC200 (£600) is sufficient. Whatever you choose, good luck with your pitches!