Wafer locks are among the simplest and cheapest locks on the marker.  The are also the most common.  The best pick to use on wafer locks is a 4 mountain pick. 

One of the best wafer lock picks you can get is in the "Grand Master Lock Pick Set LPK 620".  If you search "Nextag.com you can find the complete set for about $99.00.  The picks in this set are made of heavy gauge steel and are mainly designed for automotive use.  If you plan on doing allot of automotive work you will want  to get this set.  However, the 4 mountain pick in this set is perfect for picking most any wafer lock.  Since the pick is made of heavy gauge steel it is stronger and you will not need to use a tension wrench.

Note:  The picks in the LPK620 set are great for automotive work  and other wafer locks but that is all.  You will still need another pick made of a smaller gauge steel for residential and commercial work.