The strongest I've ever gotten was this stuff called Purple Erkal. Awesome purple buds that looked like they had been dipped in sugar. Incredibly potent stuff. I mean scary potent, the type of stuff you need to be careful with. One hit usually did the trick and I don't think I ever had more than 2-3 hits at a time, just no need. Only thing was it was 100% indica and it usually wasn't too long after smoking that it'd be nappy time.

My all time favorite has to be Jack Herer. Another really potent strain. Mostly sativa so you get a nice, up high but a bit of indica thrown in for the body effects.

My guy has a Trainwreck/Purple Kush cross-breed right now and I'm planning on picking up a 1/2oz. Could be a new favorite.