I read an interesting article from Kurt Shintaku regarding the reliability of flash media.  I never really imagined that I had to worry about a flash drive failing but it seems this is pretty common:

The fact is, repetitively using the remaining available 200MB of flash space over a period of time (let's say a year) can flat out burn out the card. It will literally use up the number of writes available for the card flash memory in certain locations of the flash card's memory.

I wonder how the Readyboost service impacts the life of a flash drive… I have a 2gb flash drive on each of my two servers and I assume there is constant writing and deleting from those flash drives… Perhaps I should use that tool Lance recommended to check the life of my drives…