new centre and fronts - ok to upgrade rears later?

[Steve]

It shouldn't be too big of a deal to hold off on the surrounds for a little while. However, depending on the kind of movies you watch (on blu-ray??) makes a difference on how much they are used. I'm an action junkie myself and they do see a lot more use than a lot of people realize IMO. You may watch movies with your old surrounds vs. with the new ones you're going to get and think you were missing out without them.