Imo keep it simple.

Look at your competitors and see what they are doing, another good place to look is the clickbank top 50 - see what squeeze pages those guys are using as you know they are getting massive volumes of traffic:
http://cbengine.com/popular-clickban...m?report=paf-2

It seems to be standard - to have a short page with benefits on one side, nice graphics, and a big opt-in box on the other side of the page. Here is one from Blogging to the Bank who recently had the highest ever Clickbank gravity:
http://bloggingtothebank.com/