Getting quite excited myself as my 02 Tdi is currently on 299,460 - my next fill of diesel will take me through the 300K barrier. It's still giving mid-50s mpg, although that got up to 60+ recently when a leaky rad prompted me to keep the revs down for a couple of weeks.
Apart from the leaky rad, which is now fixed, I also had to fit a new exhaust last October. MOT is due in April.
Edited to add : my air-con also broke after a couple of years and I had to pay an independent to fix it.
Edited again to add : I've just noticed that I've been a member since I bought the car but have only posted 6 times... :-(
AJ.