We don't have an engine to simply click some radio buttons and fire away the results, so everyone will have to copy/paste the categories and fill up next to them his/her choices. Find below the categories and just some suggestions which are there just to show what goes where. Fill up your choices, don't get influenced by the samples.
Best Hobby OS [e.g. SkyOS, AtheOS, MenuetOS, Syllable etc etc]
Best Desktop/Workstation OS [WinXP/2k/NT, Win9x,* BeOS, Linux, OSX, etc etc (no individual Linux distros here)]
Best Server OS [e.g. Solaris, IRIX, Win2k, FreeBSD, Linux etc etc (no individual Linux distros here)]
Greatest OS/distribution surprise of the year [e.g. Lycoris, Gentoo, OSX, OpenBSD etc]
Greatest OS/distribution dissapointment of the year [e.g. Lindows, QNX, AtheOS etc]
Best desktop environment [e.g. Aqua, Luna, KDE, CDE, BeOS/Tracker, Gnome, Syllable etc.]
Most profound application of the year [e.g. Mozilla, Photoshop, Evolution, Outlook XP, OOo, iCal, KaZaA, VS.NET, Eclipse etc]
*Note 1: WinXP, NT and 2k are considered the same OS (they share the same core). Win95, 98 and ME are the same between them, but not against XP/NT/2k (Win9x/ME doesn't have the same core as XP/NT/2k).
*Note 2: Please stick to the pre-selected categories. Not that it really matters, just for consistency's sake. We don't want to confuse readers. :)