I do not know which is best for battery life/performance so please discuss that below, if you find any radios I do not have listed please send me a message with the link so I can update the thread.
Note: Flashing RIL files will not improve battery, stability or enhance anything despite what people think, you are wasting your time, lookup what the RIL actually is and the example source code and you will see why.
Old eclair radios
Instructions on how to flash the radios can be found here.
NOTE: If you have the Alpharev Oxygen or CM7 HBOOT then you will not be able to flash these files via recovery, quote from AlphaRev site below.
If you downloaded Bravo Data++, please notice the /cache partition is too small to hold Radio flashes from recovery. You can however flash the radio just fine with 'fastboot flash radio radio.img'. Just extract the radio.img from the radio update.zip beforehand.