Right now probably one of the most needed applications would be a complete system BACKUP from N900 to PC capable of backing the whole system files including all contact information, apps personal settings etc etc eMMC included in a format that can be used directly for a complete restore for example a .bin file ready for flashing the device back to a known working point of backup. This would be very beneficial for everyone from programmers to normal end user's that will take the worry out of installing and experimenting in general knowing if anything goes wrong it can be reversed by a simple restore flash when a loop situation occurs for any reason I think an application capable of doing this would go a long long way for the N900 for many reasons.