I still hum and hah about rooting my Desire HD.  I used a Gold Card to take it off Orange UK and install the generic HTC ROM, but wonder whether rooting would make the Gold Card unnecessary.  I have not really got a handle on what a Gold Card actually is yet, so am pasting my research here:

androidtipsnapps.com tells me what a Gold Card is:

A GoldCard is a special SD card which, when inserted into your device, allows you to flash RUU files with a different CID to your own device. For example, if you own a T-Mobile branded device, this will allow you to flash a generic ROM.

A bit of googling of CID tells me it is Carrier ID, and xda-developers has two useful entries:

CID

The CID (Carrier ID) of the device is a setting which determines which carrier ROMs should be allowed to run on the device, a table of valid CIDs can be found in the wiki pages. All bootloaders (apart from HardSPL and SSPL) will only allow a ROM with the correct CID to be flashed onto the device. A device which has been CID unlocked will have SuperCID which allows ANY ROM to be loaded onto the device, SuperCID also unlocks the Ext_ROM and allows it to be mounted.

CID Unlock

Load any carrier ROM (in any language) on the device.

Which leads me to suspect that I should be looking for CID Unlocking.  Is that different from SIM locking?  xda came to my aid again but this does not tell me whether I need a gold card once I have rooted the phone.  I then finally did the obvious:

androidcentral.com suggested that you don’t need a gold card after rooting as did addictivetips.com.

I’m still left with the dilemma of whether to root it or not though. 🙁