UPDATE: Yes, currently Twitter will notify you if someone favorites your Tweets, if you have your Settings -> Notifications -> checkbox, checked for "My Tweets are marked as favorites".
Currently, Twitter will send email notifications for the following:
Messages
Email me when
- I'm sent a direct message
- I'm sent a reply or mentioned
Activity
Email me when
- I'm followed by someone
- My Tweets are marked as favorites
- My Tweets are retweeted
To change your Twitter notifications go here: http://twitter.com/settings/notifications