Yeah, I'm not talking about just converting RAW images to JPEG. I'm talking about manipulating the RAW file to prep it for professional submission - which might include curves, levels, touchup tools (healing, etc.), possibly some filters, swapping out backgrounds with content aware, and I'm looking forward to playing with the new puppet warp when I upgrade to CS5. All of this with "layers piled high" as our friend above says, and all on 21MP RAW images.
That's my definition of "serious" photoshop.
I am wondering same thing as you! Currently working on late MBP 13 2009 and lightroom is lagging sometime! Trying to do some video editing from my 5D Mark II is a nightmare! I was gonna go for the MBP 15" 2011 but it will be super heavy! May be Ill pick the MBA for photo editing on "the go" and adopt the iMac one of these day.......Apple just keep emptying my wallet!