I've been using Opera since version 5.04, supported by ads also, and it still works flawlessly for me.
Yep, I tell people it's the best out of the box also and install it on everyone's computers that I touch.
My Opera works just great on any site I visit and I don't give a crap about Facebook or Twitter anyway! Works perfectly with Gmail though.
My Opera is using all of 86K memory right now. Whew! Almost out of memory, better shut 'er down!!
You think your machine is top notch, then fine. If you're happy with it, rock on!!
With the list of browsers that you've used and either don't like or don't do what you want them to, then you're SOL as far as any other browser to use as an alternative then!