I'd try a set of the Imagine B series monitors before the towers. A poster hear (Brian Fineberg IIRC) went from B6s to the Imagine Bs and report a real nice increase in sound quality. At he reports that they still match well with the C5 center.
Plus they're less expensive than the towers.
Another option would be to go for the larger B6 and a better, more tuneful sub.
Plus they're less expensive than the towers.
Another option would be to go for the larger B6 and a better, more tuneful sub.