Going from 2 computers down to one...

Need some opinions.

I currently own a 2011 13" i5 Air and a Dell Studio XPS desktop (i7, 8gb ram, decent video card). Currently, I use the desktop for all of my photo editing (of which I do a lot) and use it as the "hub" for some of my media. I use it in conjunction with an older 22" lcd.

I don't really enjoy having two computers (the Dell and the Air) and was thinking about going down to one. Additionally, I'd really like to have a larger and higher res display.

So I'm thinking about two options here:

1. Keep the Air, sell the desktop, and buy a Thunderbolt display (using the Air as my only computer)

2. Sell the Air and desktop and buy a new Retina MBP

I enjoy the functionality of a laptop and feel that I need to have one, but most of my computer work is done at my desk. I'm afraid that if I go with option 2 that I'll get sick of the small monitor of the RMBP (even though its high resolution). I'm also concerned about the relative lack of horespower from my Air when used for more intense tasks (lightroom, photoshop, etc). I'm also concerned that I'll kill the battery of the laptop by using it as a desktop (and having it plugged in all the time). Since they are non-removable, this is worrying.

So, not sure what to do here. Any thoughts?