My FI and all of his groomemen are wearing chocolate brown chucks.
I don't know if anyone else is doing that but we are providing the shoes for all of the guys and right now they are having a sale on the "slim chuch taylors." They are originally $55.00 and are on sale now for $39.99 but if you order before 01.22.12 you get an additional 25% off any sale items so they end up being $29.99 per pair which is an good price for them!!
Whether you need them for 1 person or your whole party it's a good price just in case anyone is interested:)