[Cleo]

I think it also depends on your workflow.

If I'm doing movies in FC or rendering movies in Episode then I will only open those programs while I need them and then quit them afterwards.

Most of the time I going between GoLive (soon to be replaced by DreamWeaver) Photoshop, BBEdit, while checking my stuff in Firefox, Safari and Windows IE while surfing in Safari while taking care of mail in Mail while chatting in Adium while doing a file transfer in CyberDuck while doing a rsync in Terminal and doing screen sharing to one of my other Macs that is doing something else. Then there are a utilitarian programs like Address Book, iCal, Stickies etc that use so little system resources that it's pointless to bother quitting them. Ironically the only program that I do leave open and can be somewhat of a resource hog is Activity Monitor, it's not that bad, but I kept it open so that I can spot something that is slowing down my system and kill it.

As someone that has been using Macs since the eighties I'm absolutely amazed at how well Mac X handles memory.