IIS vs. Apache
I currently run a full 2000/.NET network with IIS5/6. It works for me no problems and I will most likely continue to run like this for a whiel. I am experimenting with FreeBSD (I like the little daemon).
To answer your question:
IIS is alot more user friendly and has greater integration with various snapins, etc... Thanks to Mr. Microsoft everything works together nicely.
Apache is less user friendly but a LOT more stable. I have had more issues with my IIS boxes than I have had with my Apache Box. By Issues I mean: Various services stopping out of the blue, IIS_USR accounts not working properly, etc.
My Advice is that if you want a web server, and you have a little time to play around. Apache on a BSD Box is the way to go. THIS IS ONLY IF YOU WANT A WEB SERVER. If you want a lot more stuff to occure, are under time constraings, or plain and simple just like microsoft. IIS is the solution.
Here is a brief summary of both:
IIS:
-> WINDOWS INTEGRATION. everything fits very nicely.
-> SECURITY ISSUES. You must stay on top of patches!
-> FLEXIBILITY. You can do some cool stuff with IIS
-> COSTS $$. Simply, how much $$ do you want to spend
-> GREATER OVERHEAD. Windows based vs. Text based?
-> EASE OF USE. Very easy to use
APACHE:
-> SECURE. Plain + Simple = Secure
-> HARDER TO USE. Not super easy to setup
-> SMALL MEMORY FOOTPRINT. No Gui loading (assumin *nix install)
-> CACHING: Apache caches a LARGE portion of the website (or maybe all) into memory so when a request is made it can pe spit out right away).
-> COST: FREE!@#$
-> PORTABLE: Comes in Win32 Version as well
This isn't definitive, but it is an idea. It's like asking: "Chicken or the Egg"?.