You'll see absolutely no benefit in performance unless you do renderings and complicated, memory-intensive work. As a matter of fact, your performance may decrease as a result of the extra memory. All you need is 256MB for a regular system or 512MB if it's networked and being used as a print/file server.
Also, if you're running Win9x/ME, forget the extra memory...get yourself a new OS.
I have 2GB of PC133 SDRAM in one of my systems (the server) and I also work on it. The performance of the system is excellent (it's a dual PIII1Ghz system with four 60GB HDDs in RAID 0), but so is the performance of my other systems, which only have 512MB of RAM (one has DDR266 and the other PC133). I too am going to get me 2GB of DDR266 in preparation for a MP AMD system however...just so I can show off, I guess... 🙂