I mean, I love EVERYTHING about their company, their stores, their entire "cool stuff in a box with directions with no words and funky names" culture. And damn, they serve this apple cake in their restaurant that you'd sell your mother for. (Or maybe you'd keep your mother and make her make you the apple cake. That's what I'd do.)
Their appeal (IMHO) is enough choices to satisfy but not so much to confuse and terrify the design impaired. You're choosing from a small collection of patterns and colors and wood finishes and everything is fit together in a little showroom you can copy! Or even if you mix and match - no one with taste will be offended!
It's brilliant.
I'd say my entire home is either IKEA or inherited furniture. We've bought pieces and moved them around to various apartments and our house and rooms in our house; the new "island" in our kitchen? My son's old dressing table. Mini-dresser in the bathroom for towels? Also formerly of the nursery.
See? IKEA makes people creative! Or at least enables us to pretend we are!