IMHO get the 09. Particularly if you like fuel injection. If you want to mod, then it appears there are more options right now regarding carbuetors (though I doubt you'll have to wait long for FI options to appear). Someone like Diesel Powered would know. Look at his mods list!
The Kawasaki web site notes that improvements have been made to the ventilation for the belt drive for 09. I have observed posts about belt failures in the 08s. Some folks have gone to after market parts solutions, so if your heart is set on an 08, this is not insurmountable. But if you're thinking 08 to save money, this might be a concern.
Hope this helps.