Interesting you don't reach full usage - I'm deep in swap most of the time. But, I don't have any performance issues until something has a memory leak or I've got too many IDE windows open.

I think a lot of us techies have also become too used to just having as many programs open at once as possible, and that of course can be quite demanding in terms of resources when you have a lot of day-to-day as well as work tools open.