I use post-name for my URL's, and I make them very descriptive for better Googularity. The problem is that when people email a link to my site, the link might wrap. I have fixed this with a clever workaround that uses the partial URL which is given to find the original post (or all matching posts). The result is FlexURL.
You can find the plugin and more details here:
And here, for that matter:
FlexURL works only in WP 1.5 so far. But I have a hack (not a plugin) that works in 1.2, also: