I'm in your boat with an 01 3.0... it has just over 200k and its time to start thinking about something newer. That said, I was in your spot at 185k... I chose to stick it out longer, and will still try to sqeeze a bit more life from her (I love the truck and I'm cheap).

I'll eventually give in an get a CPO'ed E70. The apeal of 30mpg Diesel is nice, but costly. probably go 3.0 again and hope that the car is simmilar enough that I can still work on it.