Martin should be given a knighthood for all he's done for us lowly consumers.
I rarely make a major purchase before checking out on there & hotdeals. The everyday shopping tips are also great - you can save a lot of money over a year by checking out specials/glitches before each shop.
The only downside is that if you thought this site was addictive, wait till you see his forums. You could spend all day on there & still not keep up with it all.