Focus group discussions
When you place several of your users (or non-users) in one room, the discussion reveals hidden meaning in your branding, advertising, services, consumer characteristics. Focused group discussion (especially in combination with the projective techniques) helps to tear out users out of the shell of rationality and understand the deeper meanings and emotions.
So if you can gather a few people at one time in one place, this is the appropriate method. Good work of moderator is half of the success of the study, so our moderators have tons of group discussions behind them.