Like the others have said, get it sim free - £610 from clove.co.uk with free goodies!!
then get a rolling contract sim - three's SIM ultra pack for £15 is good enough for me, Unlimited texts, Unlimited internet, 1500 talk time. (£360 over 2 years, plus the phone from clove, that is £960 for 2 years total
if you went on contract with the phone, you would be tied up with it for 2 years or so, at approx £50-60 p/month maybe a £60 deposit for the phone = very close to £1500
do the math, it works out better in the long run if you get sim free phone and sim only plan.
[CWM] RAFDROID HD 4.2.0|Froyo DesHD|Most Stable Rom [Rafpigna 2.0 OC] for HTC HD2
was running Samsung Galaxy S2 GT1900 till it blew up last week
(got hot while playing games and screen went crack if anyone wants to know)