If you can afford to buy it outright, that is the obvious answer, in order to avoid finance / interest costs.
However, if you are self employed, there is some great tax advantages to contract hire, although you will never own the car or be able to but it at the end of the hire period. (you can however, get a family member or friend to 'buy' it from the finance company at the end of the term - they usually do not mind and are just obeying the law, relating to the fact that ex-contract hire vehicles cannot be sold to the actual hirer).
If you are employed and prefer finance (for some reason), try to hunt down a 0% finance deal via VW and spread your payments. You ARE paying 'interest' on it however, via the actual car cost. With that in mind, I would recommend a nearly new model to avoid the rapid depreciation of a new vehicle.
I bought my wife a 3 yr old, 2.0 GTi Golf last Christmas and paid less than 6k, from a dealer, by hunting around and driving a hard bargain (pardon the pun!!).
Hope that helps, good luck