Another vote for Paselas, which would be ideal for this bike. Note that Gatorskins might not be a step up performance-wise from your Kendas since they are fairly stiff tires due to the sturdy puncture protection layer. However, they will protect you somewhat from punctures if you live in a place with lots of road hazards and goathead thorns. Yes, definitely stick with wired on tires if you don't have hooked rims (highly likely with a UO-8).