well with me it all depends on the engine....
for example...if its an L36 i don't think i would get one with anything over 50K...now say if it was an L67, LN3, L32, L26, or L27 I would take it as high as 100k.
Now I would include transmission in there, but its so hard to tell whats transmissions are good and which ones are bad. I mean because, sure, people change their oil all the time, but most people don't even think about the transmission, what it does, they just think that changing the oil covers all that. I am not gonna say most, but ALOT of people NEVER change their trans fluidm and then you have some people that are religious about it. And even if they tell you the car has been well maintained, I would always ask them, PERSONALLY, "what is the transmission fluid and filter change interval" and if they would tell me any figure above 20k, "Good luck with the sale"
So there you have it. But in general, I like any car that has under 80k.