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This statement suggests you're unfamiliar with modern cpus. Turbo boost has limitations. It's not just 2.9ghz for a sustained period of time at will. The imac is obviously clocked higher but with an older architecture. You can't just pick out whichever is larger.

I'm surprised you want to go from a 27" display to an 11". Have you spent much time with a small laptop display? Did you require portability? Personally I'd suggest the 13" especially as it bumps you to 4GB of ram which is the least i'd suggest specifically under Lion. I know I'll get comments that the ssd negates this, but ram is still superior, and the 13" display is much easier to look at for extended periods of time in my opinion.

I would use the Air with an Secondary Monitor which I would use if I'm at home, so the 11" would be no problem for me.
 
My 13" MBA is my only computer since I sold my 2008 15" MBP a few months ago, and I'm perfectly happy with it. Granted, I'm not a gamer, but I am online, and writing for hours almost every day, and I find the MBA excellent.
 
This statement suggests you're unfamiliar with modern cpus. Turbo boost has limitations. It's not just 2.9ghz for a sustained period of time at will. The imac is obviously clocked higher but with an older architecture. You can't just pick out whichever is larger.

I'm surprised you want to go from a 27" display to an 11". Have you spent much time with a small laptop display? Did you require portability? Personally I'd suggest the 13" especially as it bumps you to 4GB of ram which is the least i'd suggest specifically under Lion. I know I'll get comments that the ssd negates this, but ram is still superior, and the 13" display is much easier to look at for extended periods of time in my opinion.

I have 4GB in my 11"
 
I have 4GB in my 11"

The base 11" model is 2GB which was why I mentioned it. It's also pretty tight on drive space. The upgraded 11" model has 4GB instead and a 128GB ssd. It's the base one that I find really tight, but 4GB of ram is starting to feel kind of slim to me. To clarify I meant 4GB is the least I'd go with in any system today even for casual use.
 
The base 11" model is 2GB which was why I mentioned it. It's also pretty tight on drive space. The upgraded 11" model has 4GB instead and a 128GB ssd. It's the base one that I find really tight, but 4GB of ram is starting to feel kind of slim to me. To clarify I meant 4GB is the least I'd go with in any system today even for casual use.

But the good thing is, 4gb x 128GB is available in the apple store and best buy.
 
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