4GB Ram is fast becoming normal, maybe less on linux than windows, but all the same. In a year or so, probably around when Windows 7 arrives the world will slowly start to stop supporting 32bit and people will be on the forums complaining because they stuck on Athlon and Pentiums without 64bit support.
For me it can't come quick enough, I already use the 64bit version of Ubuntu, I have 6GB Ram so I don't need a swap partition on the disk. Personally I think its faster, but maybe I just want to believe that to justify my RAM.