Id buy outright were you can. I agree circumstances and priorities can change and if you've bought the car no one can take it off you and its yours. Leasing is good if you have the money but all the final payment crap scares me and so many people just trade in and lease another - so never own their car!
We looking to change atm and I like the look of focus's or seat Ibiza's. My budget is really low but, think we'd get about £700 for our car and can only really stretch to add another £500 to that as my job only temporary.
I agree check out auto trader for idea's - you can do an advanced search of number of doors, petrol, price, mileage etc and it brought up a few good deals on models I hadnt even considered.
http://www.autotrader.co.uk/search/used/cars/postcode/bt282au/radius/1500/quicksearch/true
^^ not sure if when you click that link it will be cars in my area, but it shows you what I mean anyway lol