1987 LX problem... battery drain?

Hey all, I finally got my '87 LX running! Now the bad news. It only runs if I jump-start it first. I've replaced the battery, solenoid, battery cables, and TFI module. I hooked it up to my Oldsmobile on Thursday,let it sit a while, and it started right up! I drove it around town for around 30-45 minutes, and then came home and shut it down. I came back about 3 hours later, and the dang thing was almost dead. The dome light came on, and it cranked over once and then nothing. I'm confused on this one. Is there somthing draining the battery?

Thanks, that helps! I was wondering though, could it be the alternator? If so, how would you suggest testing to see if it needs to be removed and tested? Also, if it does need to be replaced, does anyone know generally how much a reman. alternator costs? Thanks!

Ok, it's not the alternator. I checked it (started it and put multimeter on pos. and neg. battery terminals), and I found that it was indeed charging. It was reading 14.6v. I've heard that the alternator output is usually around that. So, in the meantime, I pulled all the fuses that weren't "vitals". I hope that took care of the battery drain.