Here are 2 plugins I highly recommend if you have problems with what email address your wordpress installation uses and if you use google analytics.
This plugin will change the from field that email is sent from when people register or anything and it sends out email. Otherwise it might send out emails as some generic account from your hosting.
Author Homepage: http://skullbit.com/wordpress-plugin/wp-from-email/
Plugin Page: http://wordpress.org/extend/plugins/wp-from-email/
This plugin will allow you to easily just copy and paste the google analytics code into a textbox so you don’t have to edit the source for your wordpress theme.
Author Homepage: http://xavisys.com/
Plugin Page: http://wordpress.org/extend/plugins/wp-google-analytics/