XBMC
OpenElec
Optimising
Turn off the RSS feed in System => Settings => Appearance.
Add ons
Bluetooth
lsusb - shows you if the device is there
Bus 001 Device 007: ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)
bluetoothctl - opens a control panel to help play with your bluetooth device. Use help for commands.
list - lists the controller show - shows the statusses scan on - scans for devices devices - shows you the devices it has found
you can also use hcitool - it has a few more options
hcitool scan
rebooting a LOT helps a lot on the pi!
LiveTV
The system needs to be running Tvheadend which takes the input from a DVB card and moves it to XBMC Live TV. It's configured through a web interface. In the Howto's there's a section on Ziggo that may apply to UPC as well.
DVB
DVB-C = cable DVB-S or S2 = satellite DVB-T or T2 = terrestrial
A list of linux (and therefore XBMC compatible) hardware is to be found on the LinuxTV wiki
Standard you need a DVB-C card with a CI interface. Some DVB-T boxen also have DVB-C compatibility and a CI card.
The HDHomeRun with TVHeadEnd is your best bet, but unfortunately this is not CI+ certified. So far, nothing is, as CI+ was developed to stop people from watching TV on their PCs.
You can find a list of raspberry pi verified peripherals at here