Re: Windows 8.1?
I moved to XP from 2000 after at least SP1 (and dual booted it with SUSE Linux). I manually tweaked security settings (and was fairly paranoid in setting router firewall settings). I found XP useful, but actually prefer Windows 7. For me, Windows 7 is the best version I have used, but then I have little or no experience with the 98, ME, and Vista incarnations (my loss, I know ;-) ).
Win 8 on a new laptop is much less to my liking and I must still get round to setting up the machine to dual boot with Linux. A single try getting round the effing EFI boot loader failed.
I will try upgrading one ancient laptop from XP to Win 7 and failing that make it a full Linux machine.