If you want secure browsing: Internet Explorer
If you are writing a script: Mozilla Firefox
If you want things simple, easy and have lots of apps: Google Chrome
If you have very low bandwidth: K-meleon
If your processor speed or RAM is low: Maxthon or K-meleon.
Remember that Chrome takes lots of RAM.
Internet explorer is advancing but its interface still needs to be improved.
Maxthon has no apps as such.
Ditto with K-meleon, but K-meleon crashes a lot.
Firefox has no problem, but I don’t like it’s interface, hence don’t use it.