For Shoes on platform, or pedals with cages I would look for something with a stiff sole. You've said you don't want to wear bicycling specific shoes. In the past I've used things like Addidas Campus shoes. They're not nearly as good for cycling as my Shimano shoes are on the bike, but they're far better off the bike.

For clothes, mtnwalker hit the nail. I have a pair of Canari mountain bicycling shorts that look like "board shorts"
http://www.google.com/products?hl=en...ed=0CDYQrQQwAg

Standard Under Armour "heat gear" in the summer, and "Cold gear" in the winter seems to work well, and isn't horribly uncommon. The Under Armor Golfing Polos are pretty good for summer time riding as well.