DSLR lifetime

Actually, this post has me thinking: what typically kills a DSLR? That is, beyond dropping it from 4 feet (which will kill a DSLR. trust me on this one. RIP D30), what are the things that will typically break in a DSLR first that will make it prohibitively expensive to repair versus the cost of a new replacement? It’s sortof like a car. As long as the engine and a few other critical components don’t die, you can keep repairing it, barring a money pit situation. So, what is the “engine” of a DSLR?

The shutter?
I think I’m okay here. I have shot around 15,000 frames, and before that I’d guess the previous owner did a third of that, but I don’t know. This thread indicates an average lifetime of 50k frames with a typical consumer EOS body shutter. So not a problem. And even if it did break, apparently it’s not a difficult repair to send in and have done – a few hundred bucks. (Though, with the plummetting cost of DSLRs, a “few hundred” quickly gets into viable replacement territory, depending on how many “few” we’re talking.)
The sensor
I am curious about this, and I have my suspicions that this will actually begin to be the thing that causes me to replace it. I don’t think that it will ever just completely die, but I already have a scary number of dead pixels (as I learned when I started doing lightning photography with long-exposure noise reduction turned off). There’s also a weird pock-mark I can visibly see on the sensor, which yields a little circle sometimes that I have to clone out. I have a feeling the sensor might eventually get beatup enough that it’s unusable?
CF card slot
I don’t know what the possibility of this dying is, but I’ve read about people having problems. And I don’t know a lot about embedded electronics, but I’m guessing the CF reader is incorporated into the main board itself, and this is likely prohibitively expensive to replace/repair. I really have no idea though.

What else? What will kill a DSLR?