So why?

Currently have a Macbook Black, 2GB etc.

Really like the look of the air, but apart from the size, what are the advantages?

I'm not sure if I'm trying to justify it to myself or talk myself out of it?

IMHO, that is the only advantage, and that is the purpose of its design. I only recommend the Air to those whose main goal is a lightweight, albeit beautiful design at the expense of HD space, DVD drive, firewire, and additional usb ports -- all for $700 more than the MacBook. Not a choice that meets my needs, but a great machine if that is what you are looking for.

My first Mac was a Black MacBook which I purchased a few months ago. Since purchasing it I also purchased a 24" monitor and Bluetooth Keyboard and Mouse. Having it setup on my desk with everything plugged in makes it a PITA to unplug if I want to take it with me.

I bought the Air about 3 weeks ago for the simple purpose of taking it with me wherever I go and it truly has gone with me everywhere.

I used to carry an EeePC around with me however I got very tired of the small screen.

The Air is everything I want in an ultra-portable. It's not something I would want to use as my main machine due to the specs, however it's by no means suffering because of those same specs.

Ultimately I probably should have bought a 24" iMac and then the Air, however I also look at it that if I need something a with a little more power to take with me, I'll take my MacBook, otherwise the Air is perfect to take everywhere.