I think Silestone's "Lyra" counters are a pretty good facsimile of marble. But here's a website with some other options as well:
http://roomology.wordpress.com/2011/10/09/alternatives-to-white-marble-countertops/

"Super White" sometimes called granite but really quartzite stone is natural not man made quartz and is almost as hard and as stain resistant as granite. I think it's more beautiful than marble and certainly more durable. The man made quartz tops like Cambria are getting better looking but I don't really like the look of artificial tops in any kitchen except a very modern one. In modern kitchens the natural stone tops don't look right.

Thank you for responses. I am going to go look at and price the Super White quartzite.

I agree I would look at the quartzite as an alternative to marble too.