With OS X 10.7 and full screen apps the menu bar is hidden to allow you to utilize that extra quarter inch? (if thats important to you)
The menu bar can be customized quite extensively (natively I might add) for status menus for iChat, display settings, time machine backups, I could list it all the options but it would take FOREVER.
Not to mention that there a numerous third party apps (Caffeine for example) that use the menu bar.
Learn the OS before you knock it.
Just sayin...
EE
Well then you are the only person that uses full screen apps. Cause it sucks. Not every app supports. Highly inconsistent experience and confusing. Try having more than 3 full screen apps open and all of them have multiple windows open. You'll be working the trackpad like a DJ scratching his table when you try to flip between apps. Not to mention that you can't expose/mc those individual windows. It's useless. No one uses it fullscreen apps.
Well heres a tip for display settings, time machine and all the other stuff: CMD+space. Fastest way to do it and adds zero clutter. The only thing you need in your menu bar is the battery indicator, time and wifi. The rest just adds clutter especially from 3rd parties. Dropbox is the only icon you can't remove.