Thanks for your feedbacks.
Although I like its format, I discard the mini because it won't be useful the day I want to use it on the couch, in a public place, or take it on a travel...
My daily use would be programming using IDEs such as Eclipse and JetBrains, and running some Linux and Unix VMs. I heard that Windows VM looks ugly under retina but I don't mind since I have an old PC desktop running finely Win 7. I don't game, just watch some youtube videos, and surf on the web.
I have played around with both retina models at my local apple store. Using the scaled mode gives you more real estate but you lose the sharpness of the retina mode, and using a resolution higher than 1680x1050 on the 13" or higher than 1920x1200 on the 15" makes it a bit difficult for the eyes to follow.
The laptop I want to get must be able to handle without issues at least my external dell 2412M 1920x1200 display, and it would be nice if it could handle 2 of them without triggering the laptop fans at maximum speed. Would the 13" HD4000 make it? Also, is the thunderbolt connector compatible with the mini-display cable I am using to connect my current MBP to the dell display?
To take advantage of the retina display, I thought I could use the retina resolution for coding and the external display for the web and other stuffs. Any feedback/experience on this combination?
Regarding my RAM and disk size requirement, my current 2008 MBP has 8GB of RAM and 500GB disk, and I don't want to compromise them

.
The cMBP could also be an alternative for me, particularly the 15" model with Hi-Res antiglare widescreen display (1680x1050).
Here are the configurations I am considering based on my requirements:
1) rMBP 13":
1.1) 2.6GHz Dual-core Intel Core i5, 8GB RAM, and 512GB Flash disk
1.2) 3.0Ghz Dual-core Intel Core i7, 8GB RAM, and 512GB Flash disk
* Based on my context, would the difference between the i5 and i7 be noticeable?
* Will the HD4000 handle without issues 2 external displays?
2) rMBP 15":
2.1) 2.4Ghz Quad-core Intel Core i7, 8GB RAM, and 512GB Flash disk
2.2) 2.4Ghz Quad-core Intel Core i7, 16GB RAM, and 512GB Flash disk
* I favored the RAM instead of CPU clock. Is the difference between the 2.4Ghz and 2.7Ghz noticeable?
3) cMBP 15": I would upgrade myself later on the RAM and disk
3.1) 2.4Ghz Quad-core Intel Core i7, 4GB RAM, 500GB 5400 rpm disk, and 512MB VRAM
3.2) 2.6Ghz Quad-core Intel Core i7, 4GB RAM, 500GB 5400 rpm disk, and 1GB VRAM
* Is the 512MB VRAM capable of handling a couple of external displays?
* Any noticeable difference between the 2.4Ghz and 2.6Ghz?
@Yahooligan: You've got nice configs!

. Did you benchmark them? Which one is faster?