It looks like you've got a fair bit going on there already. Bear in mind that menu bar applications are just like any other: they take time to launch and memory to run. The more applications you run, menu bar or no, the slower your computer will be. I would avoid running anything you don't absolutely need, rather than deliberately trying to go the other way.
I already have too many startup items, but I do need all of them running while my computer is on.