Recently bought an LCD TV for my caravan from Currys online.
Great thing is, you can return it to your local store if unsuitable. I guess Dixons, comet etc would operate in a similar way.
Incidentally, if you do buy online - do a search for 'online coupon codes' or 'voucher codes' - this is just a code you imput at the online checkout. There are various ones - I saved the delivery charge and a further 7%! A real bargain as the TV was considerably cheaper online rather than in the same store local branch in the first place, without the coupon codes.
These coupon codes are available for many stores, including Tesco online grocery, where I saved