IStealtherI
Well, yeah. Of course. Without a decent OST, it doesn't enrich the experience.
One thing that strikes me with Anime, are the emotions in a series. A decent OST really does help bring out and elevate emotions. Make me cry like a little girl. Except for Lost, Anime is the only form of entertainment that can do that for me.
Though, that said, it also depends on what your watching. Cowboy Bepop for example is bluesy, right? It doesn't need a sensational, sweeping and orchestrated Soundtrack. It just wouldn't fit the theme. Though, I've never watched Cowboy Bepop, despite it's acclaim, it just never struck me as my kinda' thing. Bepop is more action and futuristicy. Something more oriental like Mononoke and Seirei has this kinda' thing. It fits. Clannad, Myself;Yourself and such, despite being a rather humourous, slice of life Anime, has a very moving and emotional core, which is brought out by its light musical score.
But yeah, a decent OST is crucial. Completely agree.