All the usual stuff for any car.
Special attention for timing belt because
they do let go. Make sure the timing belt and aux belt and dephaser have been done by a specialist, phone the seller and ask first, that way you can check here if they're a trusted specialist before you waste your time looking at a car that's been done wrong.
Ask about wheel bearings and when they were last done as they can go quickly too.
Other than that you can tell more from a good test drive than from anything they tell you.
Be suspicious if the cars been warmed up before you get there. Check the oil (I've seen one with oil halfway up the dipstick, literally half way up the whole length, and that hadn't been run for a while).
Ask the seller to push the hazard light button. Chances are it'll break and the lights will be stuck on. No big deal but let them pay for it. CD players can be iffy too, sometimes they won't read discs, sometimes they won't eject them (take a blank for testing).
Check the exhaust isn't hanging off and don't be shy about lying on the floor and taking a peak at the underside, I did when I bought mine. Although I didn't know to look at the exhaust rubbers so I didn't see the cable ties and sockets holding it all up.
You could always take a local CSer along, I'm sure there'll be plenty of offers
