First of all, i congratulate you for making such a good product, i use "plugplayer for ipad" to play media off my DLNA server, here are my suggestions for future improvements
As pointed by other users there is no dearth of screen space in ipad, so the left pane can be made a little bigger, making the scrolling track/album names a little less frequent. The smallness of the left pane is sharply noticible when using album art to make selections.
The right pane can be used to show album/folders/tracks too, as media formats such as mp3 and others have a wealth of information, this info can be used to show tracks grouped by artists/albums/gener/folder etc., also the larger right pane enabels larger thumbnails of album art to be displayed.
Thats all for now