Hey, can I vote for myself? If so, I nominate StrifeMan, too!
If not, I guess I'll nominate Xylia - her wicked cool design and uniqueness as a Navi should encourage others to make their own, unique characters.
That awkward moment when Xylia was already Navi of the month, last month. If I cannot nominate one of my own Navis, I will nominate Incendina. That gigantic amount of armor and regen truly makes her a tank to be feared.