I am sorta at a half and half on this. Sometimes I can read the Manga and enjoy, but then watch the anime version and hate it.
Manga seems to be about the same price as the DVD's in my opinion....here in America anyway. I like the fact that I can read Manga just about anywhere in peace. But then again I like to see the movement of the characters. Haruhi's dancing would be no where near as cool in a manga. (Assuming there is a manga of it)
It really depends on the situation for me I guess. So....I am neutral ^_^