QUOTE(misha @ March 22 2007, 12:16 PM) [snapback]102308[/snapback]
Do I really need the 30"?
Yes.
I was right there 6 moths ago. I figure an Apple Cinima is going to last a good few years - I'd be surprised if you replaced one in less than 3 years - it'll probably go longer. It's your primary interface with everything you do so less cramped is always better.
You can certainly run "both screens" with your laptop being a second screen, that works in theory but in practice it's kind of hard. You always need the MacBook open and taking up desk space. If you've got a huge clean desk, that may work but for most people, it'll be more cramped that it's worth. Plus it's hard to see the little size writing on the MBP screen when it's sitting 5 ft away on the table next to you.
On my 30", I can edit a full portrait 8 MP image at 50% without loosing any of it off the bottom.
On the (slightly) down side - Lightroom seems to chug a bit when I have the monitor hooked up - it runs faster when it's just my MBP. I think it's having to re-draw larger versions of images due to screen size, even if I "render 1:1 previews". It's not as bad now with the production version of LR though.
Anyway, it's a few hundred dollars extra for a screen you're going to spend a few thousand hours looking at over the next few years - seems like a pretty good invesment.