[mryan]

My personal opinion is that this is a bad idea - unless I have to use a specific software package, asking for my contact info before I try your software is enough to make me close your website and go on to the next one.

Beginning the download is the first thing a user does after deciding "this looks cool, I'm going to try it out" - do you really want that first impression to be a negative one? dreamux seems to have nailed it - make it easy for them to download, and even easier to contact you to purchase when they are ready.