Dude... Firstly, check over your post before you click reply. It can be pretty hard to read. If English is not your native language then sorry.
And Firefox is not for people who use macs... Its for Windows/Macs/Linux/Unix/Solaris... basically every system out there. You only need to spend time customising it if you want to. Basically there is 1 or 2 extensions that I feel are essential and they arn't that hard to find.
About the compatability... IE is broken, and they havn't fixed it for IE7, and that makes me sad. I'm just starting to get into CSS with making my website, and am wanting to do some really fancy stuff but IE's compatability really lets me down. Check out
this site for a few examples. I spend quite a good few hours a day on the net and I maybe come to 1 site every couple of days that doesn't work on FF. That isn't most.
Now yes there are many many different ways for find out how to get IE7, but we shouldn't hint where. If someone want to get it, they can search for it... its as simple as that.