If that is indeed the only thing stopping you from using it, you can port your existing number to Google Voice.
http://googlevoiceblog.blogspot.com/2011/01/port-your-existi...
http://googlevoiceblog.blogspot.com/2011/01/port-your-existi...
This is definitely not for everyone, but if you look at the comments from users, you'll see why people are using it:
https://chrome.google.com/webstore/detail/dkfhfaphfkopdgpbfk...