Something I see quite a good amount of with Drupal modules is a tendency to hold onto fixes committed to CVS for some time. I believe this is counter productive. While yes, it is good to hold onto new, big features until they have simmered for a while and proven to be stable, smaller updates and especially bug fixes, should be rolled out regularly.

One of the difficulties with Drupal is that with so many modules needed to make a good site you can end up with a dozen or more different CSS files. On occasions when you need to tweak the CSS to match a specific design, or fix something for IE6, it can take quite a while to dig down to the exact definition you need. You might try throwing random snippets of CSS at the problem to try to make it go away, but they usually won't work.