Somehow I have managed to delete the recently added, purchased etc playlist on my Ipod. Does anyone have any idea how to get them back. They were really useful!

If you are talking about the pre-loaded playlists that come with iTunes, then it's quite simple. You just need to make new smart playlists.

Got to File>New Smart Playlist

For Recently Added:

Date Added is in the last 2 weeks.
Check Live Updating

For Purchased Tracks:

Kind is Protected AAC Audio File
Check Live Updating

For Recently Played:

Last played is in the last 2 weeks
Check Live Updating

For Top 25 Most Played:

Limit To 25 items, selected by most often played
Check Live Updating

Hope that helps

Excellent. Thanks