I say, go with the 2.4ghz. You will notice it in the long run, and when moving folders, editing movies, and overall performance.
And the integrated graphics is crap anyways, so having the x1300 integrated will get you better of then the GMA950...
And crimson is right; The CPU and GPU are two things in which cannot be upgraded in the future, unlike the RAM. Keep your upgrading options open, so you don't bottleneck yourself in the future.
So once again, i say you pay the extra, and set yourself with a great notebook for a long while
Good Luck
~Joe