I have the same problem. The old ones were RWD btw. Anyways, i lose about a quart of oil every 3K due to age and design of this generation engine. These engines will last long time, perhaps to a max of 225K. But of 98-02 Corolla, cannot be driven rough. That gen. was a joint-venture between GM & Toyota @ California Nummi plant, which was closed a few years ago, and joint-venture ended in 02'. It is known for engine oil burn-off problems in piston rings, comes out tailpipe as white smoke when high reved. I don't like the idea of "getting the leak fixed" because it probably can't be fixed or fixed at low cost, such that it either might not solve the problem or it'll make it worse due to tampering. Autozone mechanic told me its something to do w/ plastic piston ring design.
As far as which oil to use, Pepboys showed me their computer database and it stated 5W-30 for below freezing or 10W-30 for warm weather.
On whether to use: conventional, Semi/High Mileage, or Full-Synthetic oil mechanics tell me either conventional or high mileage should used because the bigger molecules of conventional oil won't leak-out as easily. Semi/High Mileage is at least 30% synthetic btw. Trust me, i know from experience after trying 5W-30 low-grade SAE-ASE Royal Purple, a full synthetic oil, and MaxLife Full-Synthetic. The RP burnt faster of course.
So far I've been using 5W-30 Royal Purple HPS, a high end Full Synthetic, w/ Purolator Synthetic, and K&N air filter, just fine. I plan on switching to 10W-30 High Mileage oil Quaker State w/ Fram High Mileage oil filter changing every 3K even though i think i can go 5K because the Fram HM filter can, and the 04' Corollas can as well.