Mozilla has recently been taking over the Internet scene with its producs, Mozilla Firebird and Thunderbird, both gaining in popularity. More and more users have been finding that their easy to use interfaces, and advanced features such as Tab-Browsing to get rid of having multiple IE windows open at a time (My personal favorite), and a flawless pop up remover. There are many themes, plugins, and extensions available for these programs. I suggest you head over to www.Mozilla.com and check them out for yourself.
You can read why you should switch to these programs:
http://www.mozilla.org/products/firebird/why/ For Firebird
http://www.mozilla.org/products/firebird/ Also for Firebird
http://www.mozilla.org/products/thunderbird/ for Thunderbird
You can also read some great online articles from Joel and also Jon Udell
http://www.joelonsoftware.com/news/20030601.html Joel
http://weblog.infoworld.com/udell/2003/06/02.html Jon Udell
There are many other programs that Mozilla has to offer, I have begun to switch over to them and have never looked back! I hope you enjoy them as much as I do!