I already know I will be highly considering the Air as my next machine, but I don't know yet whether I'm going to go 11" or 13".
I like the resolution of the 13", but I love the smallness of the 11". The 11" still has more pixels than my 2010 MBP so... But the 13" has a lot more than that.
I like having an SD slot, but I rarely use it. Like rarely. So it's not a deal-breaker. In fact, with my setup, all I would do is plug any media into my Mac mini and transfer anything I need to my external HDD.
I can't believe they took out the backlit keyboard. I have grown reliant on it so not having it would play a big part in my decision to go Air or not.
I have 8GB RAM right now, so whatever model I get will need to have at least 4. So I would add it if needed.
I don't even need 128GB. I've discovered that I have so much stuff on my SSD in my MBP that I don't need so I've moved most of it to a portable 1TB HDD. I've gotten down to 65GB on my SSD with 10GB of movies I can easily move out of my Movies folder which would take it down to 55GB with an easy 9GB free. I'd also deactivate the sleep image to save the 4GB that would be taken up by the RAM image. (I never let my laptop sleep all the way down to 0% and even if it did, Lion will be designed for easy pick up from last place. But if they bumped the low end to 128GB I wouldn't cry.
I also like the lightness of the 11" vs. the 13". The 11" is literally half the weight of my 13" Pro. And an inch narrower.
My wouldn't minds:
128GB in base 11"
Maybe higher resolution in 11"?
4GB base across the board
My wants:
Backlit keyboard returns... please!
Simple really. A 128GB 11" with 4GB for $1000 would be a definitely buy even if it didn't have a backlit keyboard. Without the 128 would still be a buy. And without the 4GB would also be a buy, but then it would need a backlight.
If all that fails, it's a 13" Air for me later this year, or a 13" Pro in a couple years. (I wouldn't even be considering upgrading so soon if I didn't have a C2D.)