I'm very interested to see how well icc works for you. From what I hear (from having a conversation down the hall with some folks who've worked on icc, if that tells you a little about where I am right now), icc is great at optimizing loopy things (ie, like games), but not so good at optimizing things that just do crap, like firefox. Also icc often makes apps bigger and slower. Moblin cannot be compiled with icc because it would be a "disaster". The toolchain doesn't compile and probably won't without major effort.
Furthermore, I agree with you, Intel cares a lot about speed. That's why possibly more effort goes into patching gcc: they want everything to run faster on IA, not just icc compiled apps.
But hey, if you can get everything you want compiled on icc and it runs faster, you win. If it doesn't, you still win because it'll still compile and run fast with gcc. So either way, if you are willing to spend the time to make it work, you win.