Although I've used Firefox ever since I got my Mac, I have to admit that lately I've been using Opera the most. It doesn't have close the number of features found on Firefox, so the main reason I use Opera is speed. It's like an accelerated internet connection.
Internet Explorer Mac is out of the question, as it's too old and not universal binary. Safari is good, but it's too slow and doesn't really have any special features when you compare it to Firefox or Opera.
I open, let's say 5 sites.
Terminate the connection.
Read stuff on sites, or write the post.
Connect to my ISP.
When it establishes connection (only) IE stalls. No connection activity whatsoever. I can see the activity in my tray and there is none.
One more thing:
The more sites opened, the longer is the stall.
But, now I'm back to the IE6. And not by my choice. Will write a new steam-blowing thread about it soon.