One of the implications of the new Vista look and feel that I hadn't considered before upgrading is the effects of the new Explorer color scheme. In particular, I've noticed that some notification icons (I won't call them tray icons lest Raymond beat me about the head and shoulders with his Windows 95 Ship-It Award) have color schemes that don't play as well on Vista. A good example is PureText, the extremely useful tool for removing rich text formatting on the clipboard. On XP the icon looks like so:
Looks OK, right? Here's how it looks on Vista:
Definitely a lot less contrast-y. Something to keep in mind when designing apps for Vista.