Well i changed my mind again, i have just ordered a 15" rMBP, will be getting delivered Thursday.
I decided if i don't go for the 15" now i will be forever wondering what it is like to own one, so i decided it was worth the extra and went for it.
I know its is way more powerful than what i need for my usage, but its the only way i can own a 15". At least it will be well future proofed and I will not need to upgrade for quite a while, and there will be plenty of extra power incase my usage does change, who knows what i may want to do with it in the future. I quite like the thought of owning an i7 Quad Core, 256gb PCIe SSD, 16gb Ram and Pro Graphics, all sound really good.
Will let you know how i get on with it.