Rails/Windows Guru Needed

We tried several different combinations of IIS, Apache, Webrick and
Mongrel on Windows with a SQL Server backend.

Apache and Mongrel packs has been the best configuration by far.

Definately. I haven’t tried IIS, but I did try Apache + FastCGI and was terribly disappointed. Now I have Apache + Mongrel sailing along just great.

Yep, I'm running IIS, Apache, Coldfusion, and Mongrel on the same
development box, no problems so far.