There are many reasons why the space taken by Other starts getting out of hand and just as many fixes. It is widely discussed both here and in the iPhone forums and you can find more posts in the "More Like This" menu on the right menu here.
First of all you may have some apps such as radio or video apps that can store content and it may get classed as Other. Email and Message attachments may also be cluttering up Other.
More than likely you had a bad sync with iTunes which may have lost the link between media files and it's data bases. In this case the music is moved to Other and a new copy is synced over from the computer. The best fix here is to Restore your iPad. If the space is still taken up after Restoring to a backup you may have to Restore it as a new iPad starting fresh.
How Do I Get Rid Of The “Other” Data Stored On My iPad Or iPhone?
With an iOS device, the “Other” space in iTunes is used to store things like documents, settings, caches, and a few other important items. If you sync lots of documents to apps like GoodReader, DropCopy, or anything else that reads external files, your storage use can skyrocket. With iOS 5/6, you can see exactly which applications are taking up the most space. Just head to Settings > General > Usage, and tap the button labeled Show All Apps. The storage section will show you the app and how much storage space it is taking up. Tap on the app name to get a description of the additional storage space being used by the app’s documents and data. You can remove the storage-hogging application and all of its data directly from this screen, or manually remove the data by opening the app. Some applications, especially those designed by Apple, will allow you to remove stored data by swiping from left to right on the item to reveal a Delete button.