i've only ever bought hard-drive refurbished ipods and to be honest they don't last me that long, but then again it all depends on the usage.
i bought an ipod mini and it broke in less than a year (apple sent me a new replacement, then i sold it to make way for my refurbished ipod 5.5G). that one broke in less than a year as well, and again, apple sent me a replacement. it's still working at the moment but a couple of months ago the hard drive failed, and using the copy and paste method to transfer the songs to the computer, most songs failed to do so, rendering the hard drive useless until the next time i plugged it in.
god knows how long this one will last me. playing games used to load in 20-30 seconds, now it takes 1-1.5 minute(s).