iPhone / iPod / iPad Sync Problems I have an iPhone 4, iPod Touch and iPad... And I have problems with syncing.

If I download an app directly to my iPhone and put it in a folder, and then sync my iPhone with my Mac, it will pull that app out of the folder and put it on the last homescreen of my iPhone. 

If I download a song to my iPhone and add it to a playlist, then sync my iPhone with my Mac, it will pull the song out of the playlist and maybe even remove it from my iPhone.

If I sync the iPad or iPod with my Mac, it will add a bunch of random apps that I either previously deleted or did not request at all.

Any ideas how I can make this a more managable process?
You might have an old version of iTunes which does not support folders. The current version is 10.0.1 so I would highly recommend upgrading. If you have the latest then try to reinstall it. This should fix your app/playlist issues.

As for the applications being randomly added ... uncheck the "Automatically sync new apps" box if it is checked. If it is already unchecked, then hopefully reinstalling iTunes will fix this too.