[artificer]

Here's my humble opinion too. I'm not a designer, but I hope some points might help.

* Make the front page simpler in content, richer in design/graphics:

In the front page, I'd put WHAT exactly is tarsnap (few words, like "Tarsnap is an online backup service for UNIX operating systems with emphasis on security" and avoid the "probably will compile" stuff, and WHY should someone use it instead of other products/solutions, in a few words. Drop the "start now" box and make a nice button instead that says "Start now with $5" or something simple like that.

Make a simple logo in GIMP, there are hundreds of tutorials for this.

Avoid listing the pricing in the front page, but make sure it is accessible from a nice viewable button. Use normal units, not "picodollars".

* Use a sans font. Serifs are nice, but seem "oldish" and are not the best fonts to describe a new product.

* I'd use blue and shades of grey as the dominant colors. Grey speaks "solid". I'd use other colors such as yellow,red etc. to achieve contrast to the buttons that might interest the visitor (pricing,documentation,legal etc)