appbrain is actually quite good, but back up your app list under another name on it as well (e.g. if it's HTC Desire Apps, save another copy under HTC Desire back up). I watched a friend (possibly an idiot) sync his list to his phone, instead of his phone to his list, blanking his list on appbrain and putting exactly nothing on his phone. If this happens to you, you can just use the back up list.
LauncherPro, Titanium for app backup, Theft Aware, Swype (not even on the market, still in beta, so sign up) or Swiftkey or BlindType looks pretty amazing
, smsbackup+ for SMS/MMS/Call log (it saves everything to your gmail), Beautiful Widgets, SetCPU (for on-demand under/overclocking, not really for turning your phone into Skynet, more for saving power, extending battery life), winamp is actually pretty good, wifi syncing etc, Timeriffic for time profiles (dim & quiet at night, bright & loud during the day, bright but silent at work, etc), ESPN ScoreCentre if you want sports info. I'll add more as my poor brains recalls them.
The best two places on the net for the Desire are Android forums
and the xda dev forums
. A wealth of knowledge and clever people on there, plus plenty of guides to follow.
Shop around for the ROM you want, don't use the first one that looks good. There are ROMS that include both HTC and Google versions of contact organisers and apps, so you can choose which one you prefer rather than having to take one you don't like. LeeDrOID
is an example (supports your native language too).