I started with a used PB in 1995 and gradually upgraded over time. I'd like to upgrade again, but now I'm at a standstill. I can't upgrade my 199 MHz motherboard without getting a whole new case, and the new cheaper memory is not compatible with my old expensive memory. I can't afford to make such radical changes, so I'm plugging along for the time being. We're about to install T1 lines at work, so at least I'll have something to look forward to!
You really might want to think twice about sinking money into the expensive, obsolete memory chips at this stage of the game -- take it from me! I wish you the very best of luck with this. Been there, done that!