I promised myself that I wouldn't get involved in ye 'ole which OS is better debate, but here goes...
If you have a high uptime on your linux box, all that means is you have an outdated kernel (and probably one of the ones that mangles filesystems...)
If you have a high uptime in Windows it means you haven't updated anything... I swear it forced me to reboot after Windows Update added an icon to my Start menu. With *nix the one and only time you have to reboot is if you want to load up a different kernel... I can even run off of the old kernel entirely in memory while it has been removed from the HD and replaced with something else. (translation: reboot when I decide)
My POV is that each OS has it's merrits and a user should pick what's best for their situation... Windows makes a great end user graphical OS, and a very awful server, while the reverse is true for *nix.
