A good processor makes a world of difference, but I might recommend another setup technique that will help.
Set the delay on your center speaker for an additional 3-5ms. With most processors you have to lie about the distance your center is away from you (say it's 3-5 feet closer than it actually is) in your surround setup menu. Most people have either have their center channel too close relative to their mains, or haven't set up the delay properly on their processor. I have found that even when the center is equidistant from you as your mains, the soundstage depth is compromised and the center speaker doesn't blend properly. The additional 3-5ms of delay solves this, as would moving the center 3-5 feet back from what is normally considered the "proper" location.
Set the delay on your center speaker for an additional 3-5ms. With most processors you have to lie about the distance your center is away from you (say it's 3-5 feet closer than it actually is) in your surround setup menu. Most people have either have their center channel too close relative to their mains, or haven't set up the delay properly on their processor. I have found that even when the center is equidistant from you as your mains, the soundstage depth is compromised and the center speaker doesn't blend properly. The additional 3-5ms of delay solves this, as would moving the center 3-5 feet back from what is normally considered the "proper" location.