Good luck finding somewhere that will insure an under 21 on anything 'performance' or on a classic policy. I had to wait to 21 to insure my XR3i due to its performance marker lol!

I'd agree with the Mk5 ZS, great chassis, good fun to drive and decent on insurance. As deano suggested a warm diesel can offer some great bang for buck action, plus they seem to be insurance friendly. I went from a Fiesta mk6 to an Audi A4 TDCI and amazingly the Audi was cheaper to insure.