I recently picked up these RainShield jacket and pants.
http://penncycle.com/itemlist.cfm?pageId=294
Very light weight and breathable. I wish they folded down a little smaller, but not bad. I'd say they fold up about the size of a T-Shirt.
I always carry the jacket, but plan to toss the pants in when there is serious threat of heavy rain. I"ve only had to pull the jacket out once so far, but was very pleased.
For shoes, I just keep an extra pair of shoes at the office along with a few pairs of dry socks. It also helps to have extra shorts and a pair of jeans at the office. Just in case.