I was looking at the same options as you. Here is what I came up with. All 13"
1) MB Air - Thin and light. But no NIC or upgradeability, wanted DVD/RW.
2) cMBP - Still thin enough and light enough. Good display, DVD/RW, NIC, and EXPANDABLE!!!!
3) rMBP - Good display, (but not worth the $$$ for me), NIC, DVD/RW, but no expandability. I want a little freedom to upgrade. Read of lag issues.
Anyone know if Apple is getting away from our ability to upgrade the MBP? Was concerned after the rMBP that our freedom to upgrade ourselves will be taken away in future versions.
BTW....ended up with cMBP and no regrets. Added 16GB ram and plan on SSD when they go down a little more.
You have to ask yourself what you want. Do you need the better display, does the lack of expandability bother you? Will you notice the lag like some have reported with the rMBP? Is the display good enough to warrant the price premium, and do you have that kind of extra cash? For the extra cost of the rMBP over the cMBP, you could build a gaming rig if that is your thing. Or get a 42" plasma for your spare room. A rockin' surround sound system. (maybe not rockin', but good). A Wii U, Xbox 360, or PS3 with games. Maybe that new chair you wanted so you can surf the web on your new cMBP.
What is most important to you?
Expandability
Cost
Display
Speed
etc.
Good luck on your choice.