first read the rules, one of which is no MS bashing, in so many words.
second, you cant keep programs like internet explorer, outlook etc, because those are applications that run on windows.
there are equivalent (and what some would say better) programs available. such as mozilla, kmail (my favorite). you just have to got to search around.
theres a good chance that most of your games will not run on a unix operating system. ID software however does release binaries for linux, so games such as quake, and doom3 (binary to be released soon) will run on linux.
all networking solutions are possible with unix operating systems. the internet was built on unix!