I adore both of them. I even ship Tonks/Luna! (seeing this pic made me squee, hee hee) :-) I remember the two were equally popular when OotP came out, but Tonks began losing popularity after HBP was released. But she's still popular in exchange fests.

Though I do know how you feel. One of my favorite characters, Quirrell, is practically forgotten. :-(

*hugs*