HTML 5, Flash
I could really laugh when people declare Flash slow and buggy and praise HTML 5.
HTML 5 *may* one day be bugfree and fast, but with pretty much untested proto type implementations in just a couple of browsers this argument is just silly.
Oh great, Quake 2 runs in a HTML 5 canvas. Slower than on a 486. Great.
QuakeLive runs on every cheap PC at maximum frame rate (granted, its a big plugin itself).
By the time HTML 5 gets widely deployed Flash may well be bugfree and faster (especially on linux).
And Apple is just behaving like jerks with their 3.3.1 clause. Give them even a slight bit of leverage and they will engage in anti-competetive bahavior.