Hm... tough question, and the answer probably changes every day. Right now, I'd say skacore or straight up two-tone. Both are pretty similar, if you really look at their themes. Except one makes itself out to be brutal and the other makes itself out to be good old fashioned asskickery. As for favorite band, currently The Flaming Tsunamis. They just broke up. D:
I like both 2-Tone and Third Wave (including Ska Punk & Ska-core).
For 2-Tone I love Madness and like The Specials, but I have many other bands I need to hear still.
For Third Wave I like Operation Ivy, The Aquabats, Mighty Mighty Bosstones, Rancid, The Toasters, Goldfinger, Reel Big Fish, Less Than Jake, Streetlight Manifesto, Mustard Plug, The Flaming Tsunamis ... and probably many many more.
Los Furios is awesome, I saw them play at Shambalah two years ago.
There's this really good band from Vancouver called Rude City Riot. You can get their album off MySpace, very nice!
BUT my favourite would have to be JB Conspiracy. Their album This Machine is fucking sweet, I listen to it everyday.
and don't forget about Dance Hall Crashers and, of course, Sublime :)