Twist drills bits may tend to wander when started in metals or hard woods. Thus, I use a “Center Drill” to create a starting hole for twist drills when I want to drill a precise hole.
Everyone should own a set of center drills. A cheap set is good enough for most things. Any set in the $15 range on Amazon will do.
See “Center and Spotting Drill Bit” on Wikipedia for more info.
Note: I am creating this blog entry so I can refer to it from other blog entries.