Theory is invaluable. But composition skills are more valuable, its about knowing when, how and why to apply theory, not doing just coz it said so in the last book you read.
I once read something that taught me how to write a song. A step by step guide to writing this little melody thing, i tell you i was laughing hard. Theory are the tools you have at your disposal when creating music (though one of the tools you must also learn is that there are no rules). Theres only so much you can do to a block of wood if you only have a drill and a spade.