I'd still be using Windows 3.1 if...
... it was possible to get video drivers for modern video cards.
... more drivers existed, in general.
... two words - USB support.
... all the best games were still only for DOS.
... it had built-in TCP/IP support.
... stability was improved.
... Win32s ran more apps.
Why Windows 3.1? It fits on the I-Opener's 16MB SanDisk and runs like a bat out of hell. Not only that, but I never did want to upgrade to Windows 95 in the first place. Damn Microsoft.
What minor (or major) fixes would it take for you to go back to the world of Windows 3.1?