Yeah.. I'm in the process of doing the same thing; switching my Human Paladin to a different server, and changing his faction, because the people who got my fiancee and I in to the game again, decided they just didn't want to do anything with us, and were too focused on themselves. So, as a result, we're both switching our Alliance toons to Horde, and relocating to our new server.
That being said, both races have their own benefit. Gender obviously plays in to personal preference, so that decision rests entirely with you. I agree that Blood Elves are the common choice, simply for the 2 second silence, and the mana boost (very useful for Holy spec'd Paladins). They're still effective tanks, and if spec'd to Retribution, still pack a punch.
Taurens, on the other hand.. mechanically, make the better tanks because of their increased Health Pool. Plus, if you're transitioning to PvP, the Stomp is a great help, considering there's a ton of Death Knights running around the Battlegrounds. I have experience with PvP as a Paladin, but suck as a Windwalker Monk; hence my post for assistance in the Monk forums. xD
Ultimately, the decision rests with you, and what you personally intend to play as the Paladin. If you're tanking with no intentions of being a hardcore Raider; Planning on playing a Holy spec Paladin -- play a Blood Elf. If you plan on doing Hardcore Raiding, and want to be a super tank -- Tauren.
Hope my input helped, even if a little.