Be careful, you might start a revolution among the GTD crew:  "Efficient-ize your Relationships: Change your partner's love language to "Gifts" :D

On, like, our second date Mark handed me the 5 love languages book (I felt the same way about it, brilliant and dull at the same time).  He is a quality conversation/time person.  I think I'm a physical touch person.  It is so helpful to have this knowledge because it at least gives a couple a starting point for why the relationship isn't clicking ("Ok, how is your love tank doing? Mine's kinda low.")

And I love Karen's point that love tanks can truly be filled by more than just a "significant other".  So true.