So the question is, how much storage do you need 'on the move'?
If ~1TB would be enough then get a Classic with a 1TB HDD then slap in a 1TB SSD when they become affordable, which seems to be on the cards for the coming year. Since the classic will take a generic 2.5" SATA package you won't have to wait for someone to produce a rMBP-specific card or pay for 256GB of SSD (which won't hold its resale value for long) along with the base model.
This is pretty much exactly what I'm thinking
The problem was going back to that screen after looking at the retina...
Overall I just find it to be a nicer machine for what I use it for, but only you know what's important for your needs. Whatever you decide i'm sure you'll be happy. They're both great.
Thanks I'm concerned that I'll have serious pixel envy if I don't go retina... There again, I like the anti-glare option - I know talk about "70% less glare" but I'm not convinced...
If you'll need addition storage anyway, might as well go with the lowest SSD offered and use an external Thunderbolt or USB 3 drive for big stuff that you use infrequently.
I went with the 13" rMBP 128GB SSD because 256GB wasn't even enough (and neither was 512GB really). And I could buy another computer for what Apple wants for 768GB.
That's why the 960GB SSD for "less than £450" sounds so interesting! I'd pretty much decided to go for the retina and continue using my external HDD for films, TV, etc but this option complicates things again...