The three R's: Rubber Renewal and Replacement

My '08 is 3 years old and has 33k miles on it. It has been trouble-free, is ridden year-round, and is parked in a carport -- shielded from sun and direct rain, but exposed to temperature extremes (well, as extreme as Seattle gets, which isn't very).

I'm starting a list of rubber bits that I'd like to replace at age 4, and am soliciting suggestions. The valve stems (already done) and cush drives are a given. I'm mostly looking for suggestions about relatively cheap bits that can cause a lot of grief as they age, such as throttle body boots and various seals.

What say you?