A while back I started getting tired of the default Outlook reply colors (yeah, I was bored...). The font picker under Options/Mail Format/Fonts doesn't let you choose colors outside the standard 16, and I didn't want to use the Stationery option, so some registry hacking was in order. After a bit of tweaking I found the key:
The highlighted numbers are the RGB values in hex, so the color I use is #1c5245 - a dark blue/green. As always, use caution when editing your registry. If there's an easier way to do this feel free to comment. (It's been said that something like 90% of the feature requests that the Office team gets are already in the product.)
The tip of the day is a keyboard shortcut: Alt+F1 toggles the navigation pane in Outlook 2003. I use the reading pane on the right, and this is perfect for viewing those emails that cause a horizontal scrollbar to appear because they contain an HTML table with a fixed width.