3 for me--firefox, IE and avant. Still using Ie mainly as I am used to it and have plenty of freeware to protect me!
On my Win7 Ultimate x86, I have 2: IE and Firefox. Sometimes, I install additional browsers to test, but this is "rare".
I have 3 browsers installed IE8 (Never use it), Mozilla Firefox (Brother browser), and Google Chrome (Mine). Chrome is so awesomeeeee
I made a few browser changes. Firefox 3. IE 6 (almost never use it) Google Chrome (UnChromed) CometBird (Gecko based)
just 2 IE8 and Google Chrome my main browser of course my PC came with IE64 too so can be count as 3rd browser
AMENDMENT: SeaMonkey 206 default Internet Explorer 8.0.6001.18702 Google Chrome 5.0.375.125 K-Meleon 1.5.4 Mozilla Firefox 2.6.8 WordWeb Pro 6.1