Is there an Apple store near you? The best thing I can suggest is go into an Apple store, see the different models "in the flesh", have a bit of a play with them, and discuss your requirements with the staff. Might be an idea to write a list of what you do and don't want from a computer so that you have a clearer idea of your requirements. Once you know what you want a computer to do for you you'll be in a much better position to make a decision for yourself.
If you can afford the retina version of this device, then certainly buy that version. You will be getting more refined technology and a fantastic machine.
If the purchase price is a concern, you will still be well served by the non-retina version, which s a fine machine in its own right.