I don't think I have a favorite beer since I rarely drink anything twice. There are a bunch of craft beer places in Philly and I like to go and pick up 6 different beers. I recently had an Ithaca Flower Power and that was one of the best that I've had. It was an IPA, and pale ales are pretty muh my favorite style, and the flavor was fantastic.
Victory Brewing Company also has some pretty great stuff out there. Helios would be my favorite of theirs but it's really hard to find. I've only come across it in 24oz single bottles. It's probably the craft beer that I've had more times than anything else.
I utterly loathe most beers though I have come to somewhat like Carling Black Label. I suppose that's mostly due to it being relatively cheap compared to everything else (~$1.80 for a quart). If I've got the money on me, however, I'm a rum/vodka kinda guy. Might be prone to giving "best beer" to Stella, though. Not that it's available at all here. :\
Heineken is pretty popular in South Africa, though seemingly more with the almost middle-aged, Afrikaner community. Still one of the more recognisable brands here behind Hansa and Castle. For me? YUUURRRGHH