Omniweb is a nice idea, but the unusable tab implementation kills it for me. I just don't want to waste that much screen real estate.
the critic you have about firefox is easy to cure; use Camino. It uses Mozilla's superior gecko engine but is a true cocoa app. Camino, imo, is still the browser to beat for speed and has a very native OS X feel. (though I don't like the new icons too much)
The latest nightly builds are really good, check it out here: http://ftp.mozilla.org/pub/mozilla.org/camino/nightly/latest/