I quite like Argos
Provided you research the item, they sell some decent items, and they don't censor the reviews - so it's entirely your fault if you buy a piece of Elizabeth Duke jewelry with thirty one star reviews..
Order and pay online. Walk in. Give reference number. Walk out with item. Total time spent : a minute.
I recently had an issue with a solid wood self assembly bookcase - it looked ok, the price was right, and it needed to be a particular size to hold game consoles. The reviews said that it was ok, but that the components could be cut more accurately. I took a punt on it anyway, and found just as I was finishing making it that one spar was more a parallelogram instead of a rectangle!
Rang up support, and they agreed that I could go to my local store with only the faulty part. Checked the new item with a tape measure, swapped for the faulty one, and completed the bookcase. I'm very happy with it; it's cheaper and better built than an Ikea offering. Their website also contains all the manuals, so it's possible to see precise dimensions before purchase.
Probably going to buy some vac bags from there tomorrow, and they're handy for printer ink too.