Safari 5.2
From the day one, when I purchased mac, i couldnt use to Safari. It was so demn slow, heating problems in youtube, bugs, loging off from websites and he was drinking my nerves in a straw.
Since I was a long year firefox user I instantly switch on him, and it was great till they decided to just pumped up version numbers. Then I switched to Chrome, he was great, light, good integration in full screen mode, almoust perfect but, I couldnt used that he is basicly addon naked. It so pissed me when I didnt had all those addons for pdf, and office support, so when Safari 5.2 came out, I thought lets give him one more shot. And its great, its very fast, love the google search integration in menu, reader option, its snapier, and it has great support for showing pdf and other office addons witch was lack in Chrome for me. Shure, I know that there are addons for it, but I was never quite happy with them.
I did a bit of html test with various browser, and there can see a great improvement in Safari in that area. Last score was 370, firefox was 345, safari 5.1.5 is cca 350. Shure, Chrome is the best with 400, but since I am happy with him in all areas I will continue using him.
Shure its still beta, but works like a charm for me.