Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
In order of priority [ IMO ] :)

1) RAM
2) SSD
3) Processor

If I could only upgrade ONE item, it'd be the RAM on the MBA/rMBP
 
If you can't store all your data, the ram won't matter.

That's what you have NAS, External Flash Drives, Cloud Storage[ least favorite ] and SDXCs for....

As for fixed storage on your computer, it'll never be enough if you have a half-decent collection of music, videos, movies, softwares etc ... :)
 
Thank you everyone for the helpful (and lively!) feedback.

Sounds like RAM is the overwhelming choice, if any choice should be made. And while I would love to get 512 in there, its not going to fit with my budget.

Interesting points made all around.

Thanks again.
 
Thank you everyone for the helpful (and lively!) feedback.

Sounds like RAM is the overwhelming choice, if any choice should be made. And while I would love to get 512 in there, its not going to fit with my budget.

Interesting points made all around.

Thanks again.

Drop about $100 on an external 1TB passport hd with usb 3.0 support. It will take less space than your charger to carry. You might get it cheaper being in the US. .

Or spend $50 for 500gb.

As fo RAM/cpu... neither are required to make the most of your Air. A lot of people are getting the extra RAM to ensure they made a right call. Especially as stated, you can't change your mind later.

It has long been an unwritten core rule for it geeks to upgrade to maximum RAM available.

Mountain Lion and Mavericks will be more than fine with 4GB.

If you're planning on using it for more than 3 years though, then get 8gb. You'd be fine browsing and running office on your Haswell in 2020
 
Given that you are putting a 12" PowerBook out to pasture, it seems likely that you will probably end up keeping whatever you buy now for a number of years. In that case, I'd strongly suggest that you choose the RAM over the processor, as it will allow the machine to cope with the more memory greedy programmes that are developed over the next few years.

I tend to buy around every three years - a cycle that coincides with the end of my Applecare. I bought a MBA in 2010 - a terrific machine that traveled the world with me - and have just now upgraded. That meant that I jumped from 2 RAM to 8 RAM - for the sake of $100 (US) or €100 (Europe where I am from) it seems a good investment to add an extra 4 RAM to the basic configuration. The difference in speed is incredible, and my new MBA (11" with a 256 SSD) is blazing fast. The model I bought also came with an i7 Core, but, to be honest, that wasn't my real priority.

Good luck with it.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.