I love IKEA. The furniture is designed to be really easy to put together; if you do something wrong, it simply doesn't fit. This shows that a lot of thought is put into each piece of furniture, and that makes me happy.
(Yes, sometimes I try to put something together incorrectly to make sure that I can't be misunderstanding the instructions. With cheap furniture, it will fit together fine and be wrong. With IKEA furniture, it becomes immediately obvious that you are doing it wrong. You simply can't continue until you do it right.)
Anyway, to me, IKEA furniture is kind of addictive. I love getting a box of particle board (+) and then, with just a little bit of instruction-following, having a solid piece of furniture. It's almost as fun as Lego! (I am almost disappointed when I am done putting it together. Yeah, now I have a functional piece of furniture that will make my life slightly more enjoyable. But ... putting it together was so fun, I'm upset that it's over.)
I also like how the styles and colors fit together, and how it is minimalist with just a touch of "design". I love IKEA.
(+) A lot of people whine about the quality. If you buy the super-cheap stuff, yeah, the quality is low. If you buy the mid-range or high-end stuff, though, the quality is great. There's a reason some of their furniture comes with a 25 year (!) warranty. They expect it to last for 25 years. From what I've seen, it does.
You can pry my allen wrench from my cold, dead hands.