Clarke for me wasn't out. Snicko said there was a noise, but I thought from the first replay that Clarke hit his own pad with the bat (hence his bat turned), and missed the ball which then hit his pad and his arm. Snicko is unreliable at best, and completely useless at worst, and I don't think on the evidence available that there is any way Clarke could have been given out.
The Katich/Murali one was interesting as well. Katich was definately out, but Katich moved to get around the bowler in the last few strides of his run, and Murali actually took two paces back to get back into Katich's path. I don't think it was intentional, but the bowler (I believe) is allowed under the rules to stand his ground but not to move to obstruct the batsman. This situation was certainly obstruction, and it involved moving into the path of the batsmen, but it wasn't intentional. Tricky decision.
Anyway, nice stuff from Hayden today. Survived some very difficult conditions early on a grassy pitch with a bit of swing around, and has played the spin well. Smith's captaincy has been rubbish, from choosing Kallis as first slip to Murali instead of Dravid, to using Inzy as his leg-side sweeper, to overusing his spinners to new batsmen on a pitch that is obviously not going to turn given the amount of live grass on it. Even Murali is barely turning it, and Vettori isn't doing a thing, while there's some opportunity for seam movement for Harmison and Flintoff. Would have made sense to use them more through the middle of the afternoon session. Ponting and Clarke were superb, aside from one poor shot for Ponting and one bad decision for Clarke. Interestingly, since the start of the Ashes, Clarke has passed 25 eight times in ten innings, but made just two half-centuries. Shows that he's got no problem getting starts, and indeed that his problems are mostly related to temprament.
Hopefully Hayden can get another century here.