Replaced the rear wheel cylinder on the drivers side (brakes) a month after I got it ($145)
Put in a whole new exhaust and fixed the manifolds at 250k ($930 for the exhaust and $300 for the manifolds).
I had to get the center link and inner tie rods replaced at 259k, because I slid into a curb and damaged the original parts. 600 dollars total. I was told that the truck had never had an alignment, as all the bolts were completely covered in rust proofing and were very tight, although, only a couple things needed minor adjustment.
Frame will need to be patched this spring, but I have a line on that so it won't cost me much, being the poor college student I am :)
I love this truck, it takes me anywhere I want to go and has never let me down! I don't drive it hard, but it takes a beating in Ontario from the winters. It even still looks good for a 13 year old rig.
I maintain it very well and run only high quality synthetic oils. I flushed the transmission and I changed the timing belt and water pump just for cheap insurance. I know someone with over 600,000kms on their pathfinder, so I know mines just getting started.
The frame is starting to rust, but the mechanic says it's nothing to worry about and is being fixed in the spring. Just a couple small holes. I will get it rust proofed again. Edit: I had the frame rot fixed for 350 dollars. All you people complaining about the frame rust should have cleaned out the frame and rust proofed it! It isn't that hard to fix either.
Gas mileage is decent too, I get about 20 mpg on the highway and 17 in the city. I think I'll probably get another 5 years out of it before it needs any big work.