Israeli public opinion
Noah Millman: East-West vs. North-South dynamics in Obama's characterization of America's role
Larison: Obama failed to reach the one audience that really matters
Arab students: many versions of "Deeds, not words"
Some signs of undercutting extremists
Daniel Levy: Still Accumulating, Not Expending, Capital
Michael Keating: Obama's speech an end, not a beginning
Abu Muqawama: Speech a bigger deal in the Western world than in the Middle East
This is a fairly diverse range of opinion, the main point of consensus being that none of this will matter down the road if it's not followed up with credible action. Disagreement centers on whether the speech itself was successful or not as rhetoric and as a tactic to buy time and the benefit of the doubt.
I have read many many more reax than this; these are linked because I consider them valuable and thought-provoking. If you only read one, I would say read Marc Lynch:
This was a challenging, thoughtful speech which will be picked at and discussed for a long time. It wasn't as revolutionary as some might have hoped, but that's not surprising -- the ground is so well-trodden that it would have been astonishing to see something genuinely new. Instead, it struck me as a thoughtful reflection and invitation to conversation, with some important nuance which might easily be missed. It was neither "just like Bush" nor a total departure from past American rhetoric.
After that, too many to make sorting worthwhile, really. Daniel Levy, Michael Keating, Larison, and the Arab students. All linked above.