1. Paid applications from android market is always downloadable again from the download tab in android market. Remember to use the same account as when you bought the apps.
2. Contacts are somewhat problematic.
a. The Backup & Restore application does not backup synced contacts. Contacts that were synced with Google, Exchange Active Sync, Sony Ericsson Sync etc should be restored by setting up the sync again. Note that Google sync is normally enabled by default on Android 1.6.
b. Android has a concept of contact groups. You can select what groups to show. They are not all checked by default. Try playing around with the checkboxes.
For X10 mini & mini pro: They are under Menu->Contacts to view
For X10: They are under the icon with three guys in the top left corner in contacts.
3. email/calender settings are not backuped according to information on http://www.sonyericsson.com/update/backupandrestore/xperiaX10mini?lc=en&cc=EN
