Ikea represents good value to us, for a lot of things. I can't afford to be snobby enough to turn my nose up at 'veneered MDF' - particularly as I've got Ikea furniture going on +5 years old that it still going strong.
There's not a great deal many places that sell furniture that I can think of that's equal value. We tend to buy a majority of items from there, but pick up bits and pieces from good ol' Argos, The Range and even Asda. I'm sure it's lovely to spend £500 on a real oak book case, but a £49 one from Ikea will do till then.