Straight Druid // Warblade would be simple and powerful. If that is what you want to play, go for it, it should be more than good enough to get you through the campaign.
If you really want to optimize ridiculously, go with a Druid // Cleric build. DMM persist for yet more ridiculousness.
If I were playing the character, however, the build would be something like this:
Druid 5 // Whatever 5 (Probably swordsage or warblade)
Druid 3 // Warshaper 3
Druid 5 // Master of Many Forms 5
This will let you keep your full druid progression, while throwing in some extra wild shape goodies, as well as a touch of Tome of Battle.