Also, on a Sun team, you can't go wrong with a Roserade that knows SolarBeam and Weather Ball. Factoring in for power boosts from Sun, and the power already getting doubled, that gives Roserade and effective 150BP Fire-type move.
Well, let's see... You get to use SolarBeam in one turn, your Fire-type moves get a massive power-boost, Synthesis and Morning Sun restore a lot more HP, it weakens your opponent's Water-type moves... it's highly beneficial. Just might wanna get yourself a Drought Ninetails