[LennonCook]

Originally posted by Zebodog: IE loads much faster

Mainly because Firefox draws it's own UI, instead of having Windows do it. It does for numerous reasons. If you don't like it, look at K-Meleon, which is Firefox's rendering engine with a native UI.
There are other reasons for the slow startup ofcourse, but these are mostly fixed in the up-coming 1.5 release (expected in the next couple of months).

has much greater compatibility

You've never done any web design, have you?

security problems are non-existant if you practice safe computing.

Actually, that isn't quite true - IE's security problems can bypass firewalls, run arbitrary code without asking you, and are generally fixed quite slowly - Secunia reports two highly critical vulnerabilities in IE that have been unpatched since 2003! No FOSS program would have that happen. Ever. Infact, mostly these vulnerabilities wouldn't be allowed into the software in the first place.

Of course, I don't visit those, er...adult sites so security really isn't a problem.

Popups. Banner ads. Random javascript. Proof of concept code that IE executes despite being told not to. All of these pose security problems. All of these pose security problems regardless of the site you are looking at. With Windows/IE, you need numerous protections - with Linux, you need at most a firewall and you are safe.