at present I haven't rooted my DHD yet want to get used to it abit more before going for the kill !
how did you root your DHD? I mean, did it all go smooth? what method did you use ?
Got my phone from Orange UK and it had all Orange UK branding on it (Orange splash screens when booting up and Orange bloatware apps on it).
The firmware on the phone was non-rootable and, as such, I had to downgrade to a rootable version. The fact that my handset was branded meant that I had to create a goldcard, so I could do the downgrade.
Actually creating the goldcard was a bit of a mission (I followed guides to do this EXACTLY as per the web and wasn't able to create one, but it didn't work for me)... I did eventually sort it though. The goldcard tricks your phone in to being able to install unbranded firmware on a branded handset.
I eventually got the goldcard sorted and then downgraded to a non-branded (stock HTC) version of the firmware, which was rootable (this got rid of the Orange splash screen and the bloatware) - this was straight forward.
From here I was able to root with visionary (temp, then perm root) - this was straight forward.
I got Radio S-Off and ENG S-Off (using the easy S-Off tools from XDA) - this was easy... one click tools that do everything for you.
Radio S-Off tool allows you to simunlock the phone and also change the Carrier ID (CID) orignially an Orange Carrier ID, which is why I had to create a goldcard, to either HTC001 (or something like that), which is the standard HTC CID or to SUPERCID - CID111111 (or something like that).
ENG S-Off tool allows you to flash radios/other stuff in fastboot (be
VERY careful when flashing radios, as if you loose power, you are likely to brick the phone... although this shouldn't be an issue, as you should make sure your phone is FULLY charged if you are going to flash anything.
I installed ROM Manager from the market - from within ROM Manager, you can flash ClockworkMod Recovery, which then installs ROM's for you - this was straight forward too, as it is just like installing an app from the market.
Once you've done the above, then it's just down to you on what ROM you want to flash... I went with CyanogenMod 7 as a first ROM and am very happy with it for now.
Hope this has helped you... if you want any more info or an help, just ask!
EDIT - All of the above will also depend on what version of Android you have... can you tell us and then someone will be able to give you advice for your specific situation?
EDIT EDIT - Just seen, above, that you are on gingerbread... I downgraded, etc. from Froyo. Although the process will be very similar, I have no experience on downgrading from Gingerbread... I'm sure that someone will be able to advise though!