I would love to try out the Nexus S. I've been using the mytouch 3g 1.2 for a while and it is aging. However it still works great because of all the great work CyanogenMod does for the devices in porting 2.2.1 to it. I love that Android is so open source and customizable.
I would love to win one as well. I'm digging these new Samsung Android devices. Samsung has disappointed me so many times in the past with shoddy craftsmanship that I would never buy another product from them again, but for FREE? Absolutely.