If you do a search, you will see other threads about the presale tickets.
Basically, it is dependent on the venue's choice of ticket agency. If they use Ticketmaster, there may be better seats avaiable to the public when they go on sale. If it is someone other than TM, and especially if it is the venue's own service, the presales will be the front and center ones.
http://mjbphotos.tripod.com
http://www.myspace.com/mikebirchmusic