Plus 1: Linux Mint + Mate
Mate with suitable adjustments seems to be closest to a decent pre-Kool-aid Ubuntu and pre Vista/Ribbon Redmond if you tweak it. (less effort than removing eye candy Aero stupidity on Vista or Fisher-Price Theme on XP to have a more NT4.0 / Win 2K / Win98 sane GUI)
Excellent on 4G CF card Aspire One Netbook (switch off the stupid slide show on Login screen!) and on a uber cored 8G RAM 2.4GHz desk top with 2T HDD. As I'm doing nothing needing 64bit, I'm using 32bit mate (the 32bit OS will host a 64bit VM on suitable CPU & Mobo). Unlike MS crippling of RAM on Windows since NT 4.0 Enterprise, it uses all 8G bytes RAM, I think NT 4.0 Enterprise was last 32bit window to allow more than 2.5G app and more than 4G OS space on 32bits?
UNIX since 1986, inc Xenix and Chromix
CP/M 1979 to 1991
MSDOS since 1981, also DRDOS and DR Multidos
Win Shell on DOS from 1990 till 1996 (WFWG 3.11) Used Win 95 & win 98 for games machine.
NT versions from 1994 (NT 3.5, 3.51, 4.0, NT 4 Enterprise Cluster, Win2K, XP, Vista (rubbish, Win 7 is a bug fix), Win 8.x. Seen 10, don't want! I have old laptops and PC with DOS 3.3, Win3.11, Win2K and XP for legacy uses and old HW I/O).
Used & maintained OS/2 for a while
Regular Linux user since 1999. (Redhat, Barak, Clarke Connect, Suse, Debian, Ubuntu, Mint).
Used Max OS9. OS X seems an expensive way to buy an eye candy version of BSD?
Mines the one with Z80 handbook in pocket.