MTBF is a theoretical measure but just console yourself with the thought that statistically some other drive is going to last for 200 years to balance out your failure after one year:-)

I'm wondering if the 7200 rpm HD option in the new Macbook Pros runs hotter than the 5400 rpm HD's. Would it be better in the long run to get the slower HD, and postpone the inevitable?

On an expensive machine used like this, the internal drive should be an SSD. Consider raid 0 for the external.