My 1.8T has done over 130K (bought it about two years ago at 114K). Still going strong and no major issues (apart from the fuse box on top of the battery failing - fairly common it seems though)
I always was told that the 1.8T is pretty much bullet proof as longs as its looked after (should be the same for any car really). Just make sure you get S/H and the car has had a recent water pump + Cambelt change and you should be fine. Take a look at the buying guide / common faults to help you avoid any real dogs.
I use my car for traveling to work every day, and manage to average about 32mpg on a 20 mile journey, with quite a bit of spirited driving / sitting in traffic. On the way home last night whilst the roads were empty after the gym, I managed to hit 46mpg. As long as you don't rag it everywhere, you shouldn't struggle with MPG.
