Jameseh

Samsung GSII;
VM: £33
VM Quad: £28
Carphone: £26 (100 more minutes, 250mb more data, unlimited texts)

BlackBerry 9320;
VM: £20
VM Quad: £15
Carphone: £12.50 (50 more minutes, 500mb more data, 4500 more texts)

Samsung Galaxy Y;
VM: £18
VM Quad: £13
Carphone: £7.50 (50 more minutes, 4500 more texts)

Nokia Lumia 800;
VM: £24
VM Quad: £19
Carphone: £12.50 (50 more minutes, 4500 more texts)

You get better value walking into a shop for the first time than you do by paying £X a month for years.