please, do NOT use the avant browser. they say on their site that it is secure, then write this in the FAQ:
"Since it's based on Internet Explorer, Avant Browser is as secure as Internet Explorer."
which makes me laugh. IE is the most unsecure popular browser out there. all avant does is take the IE rendering engine (complete with insecurities yet to be found!), and add things like popups blockers to it.
from a web developer stand point, it also does not support any more of the "standards", such as CSS2; again as it is based on IE.
firefox supports far more of the standards than IE does. it's also inherantly more secure. it does all the popup blocking and tab setup you will ever want (maybe with the odd extension too, but thats what makes it so great), and what's more, it's free software! you yourself can improve it if you know what you're doing. the community surrounding it and improving it is huge. get firefox.