Take a look at what the rest of us are wearing - lots of ideas. Plus as you are watching the bike commuters for gear tips, you also get to oogle their bikes!
Some folks just ride in their normal bike clothes on rain days, some go all out with rain pants and rain jacket and booties.
Full fenders are crucial! And they give you "street cred" here! 
(which causes me much amusement when I see comments from other places worrying that fenders will make them look silly - in Seattle serious riders, commuters and racers, have fenders. Club rides require them, too.)
I sweat too much to wear rain gear. On dry rain days I just wear wool and let it dry on me at work. Wet rain days I will put on a light running jacket http://www.teamestrogen.com/prodBR_220214.html and a pair of rain chaps http://www.rainlegs.com/en/home The jacket and chaps do a good job of keeping my work clothes dry without getting sweaty.
If you have panniers you can tuck the jacket and chaps into the pannier so you always have them with you. Then it doesn't matter what you are wearing, you are ready for rain. They don't take up much space and are quite light.
Any shoes you'd be willing to wear to walk 2 miles in the rain will be just fine on the bike for 2 miles.
As far as motivation to ride in the rain, I dunno what to tell you there. I grew up here, and love to ride and run in the rain.
Last edited by KnottedYet; 05-07-2011 at 08:51 AM.
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson