Air or Macbook Purchase Decision

Question

So I am considering a laptop upgrade.
Currently own a 1.5 Ghz 1.5GB DDR SDRAM Powerbook G4.
Am considering a new Macbook or Macbook Air.
How much performance difference I am going to see jumping from 1.5 Ghz to 1.6Ghz?
How much from 1.5Ghz to 2.4Ghz?
I.e. - I want a smaller, more portable laptop that is faster than what I am currently using. I loved the Pro, but 15'' screen is just too big. I have reservations getting the Macbook because of screen complaints.
Programs I use daily: Safari, Microsoft Office apps, itunes, ical, basic stuff etc.
Programs I use once a week: Dreamweaver, Adobe Photoshop and Ilustrator.
Other info about me: I edited two feature length documentaries on my Powerbook as is using Final Cut Pro. I do not anticipate doing any more film work like this, but would still like to be able to access these files on my new machine. Basically, if I could do it on the powerbook G4 I imagine I could do it just fine on any of the new machines.
Considering: (with Education Discount)
Macbook 2.4Ghz $1,499
Macbook Air with 1.8Ghz upgrade $1,869
Refurb Air 1.8Ghz $1,499
Refurb Air 1.6Ghz $1,349

Answer 1

Congrats, Jane! That is the experience I had with my first MBA too -- although I did just upgrade to the new MBA ssd...
As to the OP - you will see a HUGE speed/processing improvement whichever system you get after a powerbook G4 -- I would think, with the things you want to do, either system would work based on how much money you want to spend. You will see a big difference no matter which you use from your PB.
For anecdotal comparison purposes -- my new MBA 128 ssd runs faster than my old Macbook Pro 2.33 -- because of the processor, the SSD drive rather than standard hard drive, and the way everyting is configured.
The processing time on photoshop is basically the same (I've never seen any kind of problem using photoshop on any of my macs, I don't know what people are doing that it takes them more than a minute or two to compile anything -- you'll be very happy with how it works after your PB)
MS Office 2008 and all other day to day software are zippy and fast, and the startup time from opening the lid to using the MBA SSD is instantaneous because there is no harddrive that has to initialize...
I think you would be happy with either one. The other thing to consider: do you need a superdrive to go along with the MBA? Do you save a lot of things to disc? Or copy data? Or burn a lot of music? If so, either get the superdrive ($99) to go with your MBA (I have one, I hate the remote disc thing), or go with the regular Macbook.
One final thing I would think about -- the Macbook is as heavy as any laptop, despite the smaller size. The MBA is 3 pounds -- you don't even feel it in your backpack or messenger. But if you carry around the superdrive as well, and the charge cord, you'll see that weight come right back to your bag.