Jeff,
My main mac is a twin G5 tower. I've only put in 1 MB of memory. I regularly have music playing, internet connection, large word docs, powerpoint and adobe reader running with large PDF files. I really don't notice any significant slowdowns, but then perhaps the twin G5 processors help this.
I have an Intel mini that my wife uses, I think it appreciates added memory more than the G5 does.
As for opticals, I bite the bullet and pay extra for the Superdrives when I order the machine.
Bob
