The Vauxhall VX220 was voted the Car Magazine car of the year. It beat ferraris, porsches and lambos to get that spot.
They've since released an even better model, apparently, the VXR220. Available in the UK. 0-60mph in 4.2 seconds. Only 60 were made and were sold for £30K. Pretty sure they've all been bought.
However, you can still get the VX220 for about £23k (from memory). 0-60mph in 4.7 seconds.
Or you could go the Lotus Elise. The VX220 is actually based on the Elise. From what i've read, for performance, you'd want the VX220.