http://forums.bit-tech.net/showthread.php?t=198623&highlight=expensive I can't remember if it was that thread or another, but it's time for sleep now anyway(Y)
Some of their staff are quite knowledgeable, some aren't same as any other high street retailer. Though I must admit I was shocked at some of the prices on the little things As an example I needed a Vga-Dvi adaptor, PCWorld was across the road so I popped in to see if they had one, I looked at the pricetag and nearly fell over £25 for something that normally comes free with a gfx card. Needless to say I got one the same brand on ebay for £1.37 inc postage
Since I've been long disillusioned with dealing with Joe Average when they say to me "oh hey man, I need a laptop/pc" I do in fact send them to PC World. I do this because I know that PC World sell stuff to Joe Average at prices Joe Average would pay from a shop, but would fight tooth and nail to to pay me. And with lots of software, trial or otherwise, which Joe Average would want on his PC.
You pay for convenience. They are there so you can get your hands on something straight away (provided it's in stock). Online can take a few days for delivery.