Well, I like to PvP as Destruction. Its survivability in arena is ... to say the least, bad. Especially in 2's. The only really good specs for 2's for the last season and a half have been SL/SL and UA (with shadow priest or rogue), but Destro can work.
As a 5/5/51 build, I would go with this:
http://www.wowhead.com/?talent=IVZ0xZxx0trhtAuAo - and 1 point to spare. Personally, I would put into either Improved Healthstone or Pyroclasm.
The reason for going for ISB over Cataclysm is that you will still get your Fire School locked out, and ISB will help with Shadow Bolt, Corruption, Curse of Agony, Shadowfury and Shadowburn. Searing Pain should be a main nuke, unless you find yourself really able to get off Incinerates and Soul Fires - and that doesn't happen a whole lot.
http://www.wowhead.com/?talent=IZ0xZxv0trGtAuAo is actually the build I use when I do decide to respec. 8% chance to daze is still less reliable than 26% chance to stun on Soul Fire (lol at Hellfire or Rain of Fire in arena). But I also find myself frequently forgetting to cast Corruption when I use a 7/7/47 variant, so I don't even bother with the affliction tree. Soul Leech is just as important in a burst comp as Nether Protection, because you don't have a healer with you, though, so I would use both NP and SL, particularly because you will still have to Life Tap for mana.
With 2.4.3 changes soon to come, Curse of the Elements will be a tremendous boon for you both, since it will affect all the spells both of you have in your ******** so it is something to consider.
If you plan on getting some good ratings, though, I do suggest going SL/SL. If it's just for fun, the by all means, spec however you like. I have heard that Shadowfury can do well with a rogue, mage or hunter, or with some kind of healer. But remember that you will be farming shards - a lot - as Destro spec.