I started a travel website in late 2009, and went through three different version of our homepage (the third version was released yesterday). The problem I noticed about the two previous versions were that, after spending 20 seconds on the site, visitors still don't know what our site does. Our current homepage hopefully fixes that problem, and I'd love to hear what you get from your first 20 seconds.http://duffelup.com/
FYI, the previous two versions are the following, both of which did not do a good job "showing" what we do IMO:
Sept 2009: http://farm7.static.flickr.com/6068/6091344748_8571cf15b4_b.jpg
Sept 2010: http://farm7.static.flickr.com/6087/6090794623_1f9b3a1116_b.jpg