Meta-Packages is a good solution for people who don't want to install a package one by one. For example, you can install gnome / KDE environment using this meta-package feature which is including all the "related" application which is important and un-important stuff. Latest Debian Squeeze update makes a funny story with some people. There's meta-package called "gnome-core" which is in my own definition it's only included gnome core package and doesn't provided any such things like email client or internet browser. I guess that's package is more suitable to be included in "gnome-desktop"
Back to the meta-package stuff, if you installed something started with "meta" so you must realize that if one day you want to remove an application that included in the meta-packages it would erase a whole stuff inside it. For the future avoid install meta-package. It's took more time to install application one by one. But it's makes you much more easy to maintenance your stuff in the future