personally i use IE and nothing else... i have Netscape 7.1 and Gecko on this machine, but both are a pain in the ass, neither have 100% Java/CGI/PHP/Flash compatibility - oftenly thing will just not be displayed becuase of this (and this is even with the Java 1.4.2 SDK Support, Plugin & Java Console and Installed in all) what script works on one site doesn't nescisarily work on another.
as for not using it without a download manager, my OC connection usually downloads things in under a minute so it isn't needed ... but that aside IE 5.5 & 6.x have built-in resumable downloads with compatible sites & ftp accounts.
It also has download Queing depending on your connection (provided you bother to set it up)
not to mention download managers are the bane of every connection, they run at godaweful rates ... even on a 56k i could be done with particular downloads faster than an ISDN user on Go!Zilla or DAP.
Add to this they also have a tendancy to LOOSE download, i remember this vividly when i used to use them to get Mircosoft SDKs back when i had a pathetic 36k.
add to this they override alot of things and also open up alot of ports which are a pain in the ass to authenticate and check using Norton/ZoneAlarm/BlackIce if you happen to use them on a secure connection.
Explorer7 will be out soon, which is a pretty awesome new incarnation ... IE might seems like its very independant in what it supports but look at what i actually supports, its the only browser i know which is capable of finishing broken code without ruining the pages download and it also is the only browser i know which happens to support everything under the sun ... and then a few things.
plus the built-in debugger helps alot at times