I don't own a car and tend to just hire one as/when I need one. Hence I've had quite a few small hire cars.
Citroen C1/Toyota Aygo/Peugeot 107 - all the same car. I've hired a few and I like them. Favourite small car. Good interior space for size. No silly toys to weigh the thing down. Good on fuel. Fun to drive. Lots of used examples about.
Daewoo/Chevy Matiz. No. Just No. NO.
Chevy Aveo. Same as above.
Hyundai i10. Nippy. Odd spec - four electric windows, alloys and fogs but no variable intermittent wiper setting, automatic rear wipe. Although it's less basic than the C1 etc. it doesn't feel half as well screwed together.
Vauxhall Corsa - all models. Avoid. Under steer in spades and in no way do they outshine:
Ford Fiesta - Either the current model or the previous one. Absolutely brilliant. The current version would be my first choice if I were to buy a car. Best handling in a small car. Lots of interior space, good sized boot. Comfortable too.
Renault Clio - French handling (if dulled down a bit through the power steering) makes it far more interesting than the Corsa but otherwise doesn't seem quite as sturdy as a Fiesta. I had a sporty version with hard suspension on hire once - good fun but very unforgiving ride. I'd had enough at the end of a 60 mile stint on B roads. The Fiesta Zetec-S has equally acute handling but a better ride.
Volkswagen Polo - I've loved every Polo I've ever driven. My last car was a 1.0 litre Polo Mk IV - I picked it up at 13 years old with 32k on the clock, and save for an Exhaust and a Battery it never wanted for anything non-routine. I've also driven more recent Polos. Second choice after the Fiesta because they are more expensive, but they're immensely practical and give a lot of owner satisfaction (imho).
Oh, one more. I've also had a Chevy Spark. Much better than the Matiz, probably better than an i10 but I'd prefer an original Ford Ka over one of these.
Ahh yes, Ford Ka. I've had an original one on hire and although it's small and not so practical with it's interior, it was a hoot to drive. Really enjoyed driving it along the Snake and Woodhead passes.
The new Ford Ka is on the same platform as the new Fiat 500. I've not tried either, but I've had bad experiences with Fiat Punto ownership and I can confirm from my experience changing a cambelt on one, they are made of cheese.
In terms of buying second hand, there are good bargains to be had but I've seen a lot of people selling cars trying to pass them off as things they are not. I've had a couple of Mondeos (they used to be dirt cheap second hand) and had two in a row with over 100k on the clock which served really well, but in hunting down those two good cars I saw a lot of duds. Cars with warning lights on left/right/centre, cars with poor accident repairs, cars with an array of warning lights on in the dashboard, cars with oil leaks, coolant leaks, clear signs of head gasket problems. It really is a minefield. Take someone with you who knows about cars, ideally a mechanic.
It was even worse when I started hunting for a Polo and in the end I went all the way to Newcastle (upon Tyne) to pick-up a good one. I think because they are a car that people will buy second hand, lots of unscrupulous 'dealers' will do all sorts of things to try and shift poorer examples for the same money as good examples. I also had the Honda Jazz on my short list at the time and it was the same story there.
Car ownership is very expensive, especially starting out at 17. It's all I spent my money on at that age and the insurance was a lot more reasonable then. It does give you a lot of independence with one hand, but in the other it takes it away because you have less free cash. A year's insurance could almost pay for a once in a lifetime holiday. Or something else, if you are starting a career, a business or there's something else you want to dip into like photography or forming a band or something.
That's a lot of information. I hope you find some of it useful. Apologies for going on a bit.