Firefox hands down... Opera is ok... uses less memory but you have to pay for ad-free. Netscape is ok... but it's feeling it's age and firefox is more secure (unlike IE), better features, and is more user-friendly, in my opinion.
Well netscape i have tried the updated version released some time ago and the interface is, how can i put this? Lame?
It looks so unorganised, if you take a quick glance at it, it would look like a random series of buttons
As for the other browsers, i would still stick with IE, although there are some issues when you visit some websites but IE has helped me alot and Firefox, i have used and have it on my computer presently, is pretty well done and i would also recommend it