I'm surprised that so many of you choose IE over FF even after trying it out. Almost everyone who I've introduced to FF have ditched IE for it and for good reason too.
Apart from being much more secure than IE, FF is also faster than IE and has far less bugs than IE.

IE has a really bad caching issue where it sometimes displays cached versions of pages...also, IE sometimes loads CSS or other documents from cache where the correct thing to do would be to reload from the original location. To get around this, a lot of developers have to send special headers to the browser if it's IE based, so naturally, I would be a FF fan

IE7 supposedly has tabbed browsing and can be skinned plus it supports extensions. But I doubt it will be almost bug free, as FF is.




:edit:
I also forgot to mention that IE does not support all features of PNG images. If they did, web design would be so much more easier and dynamic.
I'll be surprised if IE7 has improved CSS support and has less CSS bugs because all those CSS bugs means bloated CSS files (so that CSS hacks can be included to correct all the IE CSS bugs)