Currently reviewing two types of homepages for software products:
What format for a software homepage will result in more sells?
I think it depends entirely on the complexity of the software (& the target market)
If it is say a DVD burning software I just want a good looking site, a download/buy button, a quick list of key features (and links to more detailed info)...
However if it is a professional Database tool... I likely want to spend a good 20-30 minutes reviewing all the details before considering a purchase.
I will say though in either case if there is a free/evaluation/trial version be sure to add a big, visible, obvious download button! Don't put any roadblocks up for a user to try your software... If they use it and love it... That's the best "proof" the software is what they want... Now the only question is price ;-)
I suggest designing both styles and running A/B tests to see the difference.