Depending on your budget, mileage, mechanical prowess, etc

I agree with automatically changing:
Thermostat o-ring with a green (viton) one, although it takes about 30 mins with the engine in the car.
Oil pressure switch (not sender)

And inspecting, possibly changing
breather gasket
breather hoses (be sure to remove the breather restrictor and install in new hose)
vacuum hoses and clamps
fuel lines (these can crack, leading to a fire that will destroy the car)
rear brake flexible lines
rear suspension bushings (see banana arm)
sound mat
intake manifold gaskets (at least check the torque on the bolts)

And consider changing or servicing:
clutch throwout arm bushings (clean and re-grease)
pilot bearing
TO bearing
engine seal
edit: forgot the oil cooler seals. Someone else mentioned this, and it's a good idea. Might also send the rear cooler out for cleaning and pressure test.

The clutch should outlive the engine seal and pilot bearing. It is the failure of these items that can lead to premature clutch replacement.

And yes, "triangle of death" is what we are now calling it.

how about "Triangle of Grunge" or Black Triangle"?

I had a problem with the "green" O ring...slightly smaller, thermostat slid in with no effort and indeed, it leaked. The "red" O ring fit fine, tighter fit and no leaks. Both are available from our host.
Normally I like Viton..in this case they are manufactured different.http://image.made-in-china.com/4f0j0...Ring-Rings.jpg

http://www.atomicpickle.com/images/red_oring.jpg

rusnak, you are the Zen Pumpkin Master. SmileWavy