One other bit of advice, wash your engine bay on the street, not your driveway (especially if you have one of those nice white concrete driveways) That nasty crap you wash out could stain it.
Make sure all your caps on the fluid systems are tight, let it cool off a bit if you been driving. Don't get the air filter wet. It's a good idea to use an air hose or blower to get most of the standing water cleared up after.