I used to have legendaries on my team... but only one per game. In Silver I had Lugia, in Sapphire I had Kyogre, and in Leaf Green I had Articuno.
Nowadays I don't like to have legendaries on my team, especially for facing the Elite Four. I consider it a nice challenge to have no legendaries there. ...And I don't think Rotom counts as a legendary, since it can breed. (I have one on my Platinum team.)
However, I might eventually try to beat the Elite Four with an all-legendary team in Diamond. That should be fun. I think that team would consist of Dialga, Manaphy, Deoxys, Darkrai, Giratina, and Cresselia... (I have yet to catch the last two though)