Genesis 501s

I have a pair of G501 towers in rosewood. What center channel and rear surrounds should I get for a 5.2 surround system that would also double as a home theater?
You have great speakers. I came very close to buying a pair myself. The problem you are going to have is finding something that sounds similar to the G501's. Its going to come down to how picky you are going to be with regards to the theatre portion of your system.

If I had to guess, the most difficult task will be in the bass region. Nothing sounds like the 501's in that respect. I think you need to list a budget and your expectations before any serious recommendations can be made. There are just too many variables. One thing I will ask is if you have considered not using a center channel and have your processor create a "phantom" center? Going that route may make this a lot easier for you. If you already have a processor, it wouldn't hurt to give it a try.
The center channel generally doesn't have much bass info. So you should look to replicate the mid and tweeter to obtain the best voice matching...

Would suggest looking at the Salk Veracity series. Sealed with Raal ribbon tweeters come closest to the Genesis spiral planars. Custom finishes available.