16 Gb vs. 8 Gb of RAM for Lightroom 3 (and CS5.5) on the Mac?

Question

Hi!
Being a Lightroom newbie -- I've used the CS apps quite a lot -- I thought I'd repost this question here (the original thread can be found at http://forums.adobe.com/message/4056775#4056775).
I've ordered a Macbook Pro 15-inch with a 2.2GHz quad-core Intel Core i7 processor. I'm going to be using it, most importantly, to run the CS5.5 Master collection -- as well as, for the first time, Lightroom 3.
My question is: should I bite the bullet and get 16 Gb of RAM right away? Or would that be just a waste of money, 8 Gb being sufficient for my purposes? That is, how much of a difference would the RAM doubling make for Lightroom use (as well as Photoshop and Bridge)? I generally work with moderate-sized images (< 200 Mb; though I may be getting a higher-resolution camera in the near future). I do like to keep several big apps open (e.g. Bridge, Photoshop, and InDesign).
The 16 Gb vs. 8 Gb price difference is, of course, huge (something like 350 euros vs. 50 euros). Money's kind of tight (I got the Adobe student discount for the software), and I feel I really should be saving up for a better camera.
Do you think the Macbook is otherwise up to the task (if I forget serious video editing, as discussed in the other thread)?
-opm10

Answer 1

Thanks!
gatorjim2000: both Crucial (crucial.com) and OWC (macsales.com) have 16 Gb kits for the Macbook Pro.
web-weaver: I don't have LR on my old computer, so I can't take a look at memory usage right now.
As for other apps, I was kind of hoping to have a machine where I could have several big apps open simultaneously. But since I'll be getting an SDD (I hope a 128 Gb isn't too little? I'll add an HDD in place of the optical drive), applications will at least be starting quickly.