Sorry, but I have disabled all mods except the Bethesda HD textures and Skyrim with Dawnguard still crashes constantly.
Alas, Dawnguard itself introduces some instability and more bugs to the game. But that's a topic being talked about in other threads.
But back to the topic of this thread, I mostly agree with what
Lexandro is trying to say and second the idea that people need to be very careful with which mods they use with Dawnguard and if something does go wrong with your game, chances are high that it was caused by a mod. There's another thread http://www.gamesas.com/topic/1402912-dawnguard-the-mod-compatibility-list/ that lists mods that have been tested and are known to be compatible (or not) with Dawnguard.
Not all mods are bad, though. But if you use them, use your head and don't just add in mods willy nilly since you don't know exactly what they do behind the scenes. Especially mods that use or edit scripts, races, or animations should be handled with care. It would also be ideal if the mod author could test their own mods with Dawnguard and check that it doesn't break anything. And if it does - fix it and tell people that it has been updated so it plays nicely with Dawnguard.