BeOS and therefore haiku is 32% at 10199 votes
http://slashdot.org/poll/2094/OS-Id-Most-Like-To-See-Make-a-Comeback
Sweet, it’s in the lead. Seeing 11% for Windows ME is a hilarious though 
…where’s OS/2 ?
[quote=starsseed]
OS/2 continues as "eComStation"
http://www.ecomstation.com[/quote]
I think he meant in the poll. There is no listing for OS/2 or eComStation. OS/2 was one of the popular OSes they left out.
Exciting OSes from past were DOS, BeOS, AmigaOS, OS/2 & Windows 95/98. Maybe also Windows 3.1 & older Mac OS 7, 8 or 9
DOS, no one really cares for anymore. Windows 95/98 today replaced by newer Windows XP/Vista/7. OS/2 replaced with eComStation with few followers. AmigaOS still alive today but competing with fairly popular MorphOS (for PPC) and to lesser extent with AROS. BeOS continued on with Haiku which is still in active development today.
Of course, in the pool.
BTW, I also mean OS I’d Most Like To See Make a Comeback …as open source !
For OS/2 there are few projects: