The Metamorphosis is really my favorite work of his, until now (he's on the readlist in a few weeks, I have to read his complete works). It is a must-read, at least for all the symbolic it bears.

His style is really intriguing because it gives a sensation of identification, of proximity that is really strong, but in the same time is mixed with some kind of self-loathing (well, maybe that term is a bit strong, but it gets to the point).