I've long been of the standpoint that if you aren't going to buy a Valve game on the PC, you're really just wasting your time. They do have things like the Orange Box available for console, but they simply aren't happy there. Valve games have always been about heavy community support, not to mention modding, and they almost universally look better on the PC as compared to console.
Add into the fact that they're cheaper for PC, you can get them from Steam without ever having to go to the store, and any PC built in the last five years can run games built on the Source engine, and there's really no good reason to buy a lower grade of the same product for more money on a console. In America, for instance, you'd be paying an extra $10 for lower graphics, a less enjoyable community, and (if it ever came to the PS3) a less supported online experience. Why?
- J