umm ... cde, kde, gnu, gnuttella, etc are all window managers
running on x-windows.
any browser that runs in x should work on any of these systems ... (of course some are integrated with the window manager, like konqueror, or however you pronounce it, in kde)
almost all systems nowadays come with a web browser, and if you have one it's best to use that one, most systems come with netscape, lynx, hotjava or something
if you want to get hold of a browser though; netscape produce browsers for almost all systems, opera do an o.k. browser for most systems,
is an up and coming free browser, and there are a large number of others out there.
you could try asking the same question under the forum for your O.S. for specifics.