I already have the X20 and it's been a great compact, excellent for when I don't want to take my 7D DSLR around with me. But I had always wanted the X100 ever since it was released. After playing around with one for a couple of days that belongs to a colleague I decided to buy one.
It has lots of the same features the X20 does but it's better. The sensor is better, the viewfinder is cool, the size and weight feels lovely, and the f2 - 35mm lens, is awesome. It's so sharp and produces lovely images.
This is one of the first images I took with it - another hotel selfie, hopefully demonstrating how nice the f2 lens looks.