As far as preventative maintnance, timing belt is the biggest one. It is reccommended to change the water pump at the same time since it involves no more labor, and I believe the part is only about $50. Also, have all the accessory belts changed, seals, and belt tensioner. The average time to have these done is 90K miles. Water pumps usually last a little longer, but if you don't have it changed then, you might end up paying another $300 in labor when it does go bad.If you don't know when any of the fluids(brake fluid, tranny fluid, coolant...)have been changed, I'd suggest checking them, if they look original, you can simply drain and refill them, or flush them. If it hasn't had a tune up, replace spark plugs, spark plug wires, distributor rotor and cap, fuel filter, and air filter. Sounds like alot of work, but after all that, as long as your motor didn't have any major pre-existing issues, it will run for another 100K miles. Make sure to keep the oil changed at it's scheduled interval.