@Ricardo: I completely agree... I can't imaging having all those distractions on my menubar. I was actually quite surprised to see this post on 43 Folders! I had to rub my eyes and make sure this wasn't an April Fool's post! ;)

My personal philosophy for menubar items is this:

1) Information Status: Is it absolutely necessary to display important information at a glance?

I guess I like to think of my menubar as reserved for super high priority status icons or commands. Most of the time, the answer to the question above is "no". I do use the wireless status and battery level on my Powerbook, since it is pretty darn important. (I don't usually have the volume menubar item since it is easy enough to view the volume level by clicking the volume buttons and seeing the transparent window.) If I used Remote Desktop or any of the other services this post mentions a lot, then I might consider leaving them on the menubar, but chance are, there is probably a less intrusive way of quickly viewing that information using Quicksilver, Konfabulator or the Dashboard.

2) Remember: Do I need a reminder icon to perform an action/use a service?

When I first started using Quicksilver, Yahoo! Widgets (Konfabuator) and Growl, I found it helpful to have the menubar icon visible to remind me to use them. Once I began to learn more efficient ways of accessing these programs (using key commands, etc.), I turn the menubar icon off.

Anyway, that's just my personal philosophy for what its worth! :)