It was short! That’s the first thing that struck me about the transcript; apparently he got through it in 20 minutes.
The second thing that occurred to me is that this is was a fine enunciation of two defining Obama traits: political liberalism and temperamental conservatism. Andrew Sullivan's wrap-up summarises this idea nicely.
What separates Obama from many political progressives is that he stands for a liberalism of imperfection. Whereas progressives often argue that liberty is a means to unlock the limitless potential of humankind and work towards an ideal political settlement, the conservative case for liberty is based on the premise that human freedom not a means to come to final answers about political affairs, but is the best available means to cope with perennial uncertainty and human limitations. I think that's the kind of liberalism Obama champions in his speech.
The other conservative element of the speech is Obama's wholesale rejection of ideological absolutism and purity, which is these days what the Republican Party represents.
The emphasis on climate change seems to have surprised American observers. What can we read into the fact that this section of the speech centered on 'sustainable energy sources'? It might suggest that the Administration’s focus will be on funding energy R&D rather than on a cap & trade scheme. Also, note that Obama refers to 'sustainable' energy, not 'renewable'. The energy future may look greener, but it won't be all PV cells and windmills.
Finally on climate change, the line about the planet being 'commanded to our care by God' also shows Obama allying conservative themes to liberal causes.
As for international affairs, the rejection of 'perpetual war' was a definite stab at the neo-cons and the previous administration, though one must doubt its sincerity. Yes, Obama has implemented the Bush Administration's Iraq withdrawal plan and is winding down the Afghanistan commitment, but there's no sign that the vast counter-terrorist apparatus created under Bush is being wound back, and the expanded drone program gives the US war on terror new lethality and reach, and greater freedom from legal restraints.