Am I going to buy another Macbook?

I'm struggling to determine what combo of devices will satisfy all of my use cases. I've always had multiple computers and I'm comfortable with it, and I use each differently.

I have a 15" MBP for everything and a PC desktop for occasional gaming.

My "problem" (I know I'm spoiled) is that my MBP is a bit too big, heavy, and expensive to constantly carry around. I use it for development and design (running my IDE, linux VMs, Adobe CS), but when I'm carrying it around going from meeting to meeting and/or lounging around the house just web browsing (which I do a lot of) it feels cumbersome and excessive.

I'm really loving the new 13" Macbook Air and am considering buying one. Since it's ultra light and portable it would serve as the device I constantly carry around the house and work and have my MBPr serve as a desktop except for the occasional work trip or when I visit the co-working space to dev.

Take cost out of the picture... Am I really considering owning two Macbooks? I know they would both be used a lot, but should I suck it up and deal with what I have?

and no, I really don't want a iPad...