Windows equiv to OO?

[K. Redington]

I wanted to know if anyone uses a outliner only app on the Windows 
platform that even comes near OO functionality. I'm slowly trying to 
find my favorite productivity app equivalents on Windows. I have bought 
a Windows laptop (the engineering industry doesn't use many Macs) and I 
have to leave both my Wife and Mac behind while I job hunt in 
Minnesota. I'm trying to get as comfortable on my HP as possible. I 
appreciate any help, please post off list to keep our list from 
straying much.

Kevin Redington