Its all a matter of opinion, the best looking could be a Lancia Delta S4
I really like the Fiat 500 at the moment and you can get those for certainly below 10K.
Hell you might one day be able to get a Delorean for under 10k, but I doubt it
and they are great looking.
Theres also the RX7, now thats a great looking car.
Like i said at the start, all a matter of opinion