I remember Netscape 4.17 or whatever it was had top dog status before IE 5. After that Netscape started charging for their browser, and then went back to free. Now, I think it uses the Mozilla rendering engine making it about the same as Mozilla and Firefox in terms of how pages look.
Honestly, as an Opera user I completely stopped using other browsers years ago. Never saw much point. At least all Windows browsers.
In Linux I'll use Konqueror for everything - even web browsing because it's just an awesome browser and file manager. I'll use LYNX for bandwidth intensive applications because it has abnormally high throughput for some reason. Opera is still primary regardless of OS.