Intel i5 2500k is £160 in the uk and ivy bridge will be about £180 on release also have you taken into consideration motherboards because you can’t use any processor on any motherboard.
best under 200 is i5 2400 but for around 200 like $209 you can get i5 2500k and over clock , i have i5 2500k and it overclocks very easily,i have mine at 4.6 and can go higher but my needs dont reguire it to.