I prefer the NextSense theme... Original one just looks so...uhhh... HTC 

Have you even root ?

When you select recovery, there will be a Nandroid option there. Then, select backup and thats it. Again, if you follow the guides in the first page, its basically already step by step on how to do it. So no worries.

Bro no le..i m getting a USED HTC Desire...just wondering, what should i check on the phone to ensure it's not Bricked before..etc etc...

just root it 1st
later only decide want to flash ROM or not

Yes, if you have rooted using unrevoked, there will be a nandroid option in the recovery.

Okay thanks all!!! Appreciate that..next step, once i get the phone..i will ask u sifus how to root and upgrade to Froyo!!

Cheers!

ok, since the "stupid bird fly first".... I will save some trouble for you. 

Nope, the rooting and flashing went all smooth yesterday, it is just the restore from Titanium backup that fail. So I will advise you to copy the entire SD card to your computer first thing first.  But some apps like Note Everything actually store the data ON the phone but it auto backup to SD Card (luckily).  I only knew this after I did the partition on the card and wipe out all data on the card and phone. 

So the basic step:
1.  Root the phone with unrevoked (need to uninstalled HTC Sync and install Hboot driver first), you can skip the Amon Ra recovery.
2.  Install Titanium Backup and do a full backup - all apps and all data.
3.  Flash NextSense rom.
4.  Flash Radio. (i did not restart/reboot after flashing rom, I did both flashing then only reboot)
5.  Reboot/restart.
6.  Find/Install ClockworkMod Rom Manager in Market. Do a ext2 partition and cache with it.  (I did 512mb ram and 256mb cache.)
7.  Install Titanium backup - choose INSTALLED apps and data you want to restored.  A full backup will cause a lot of problem coz i think the restore try to restore back the old system files, so you will get a very unstable system - force close everywhere. 

I hit the wall on step 7 when I did a full restore.  So at the end I pull the battery and did a full wipe out of the whole phone - get back what I have after step 5 - a clean phone.  Then i installed my apps one by one manually.  But i checked Titanium backup and notice I can actually restore some of my data - sms, some apps data like SplashID, wi-fi settings, etc.  You just need to choose carefully what to restore.

walau..REALLY HELL if want to downgrade. So what should I do now. Any other method?

Yea, uninstall HTC Sync while keeping the Driver. You don't have to reinstall it if you're not going to use it

As long as you have the Driver, then you can proceed with that regardless of keeping the HTC Sync or not.

I just follow it.  Wipe data/factory reset only done on your phone memory, the SD card will not be wiped.  Only when you make partition, the SD card will be wiped out.

titanium restore (DO NOT do full restore.  Restore your apps and data one by one manually) should be done after your last step "DONE!"... 

yes, correct, after flashing rom but before partition, free space of phone only 67mb.  after you do partition, the free space increase to 132. 

software: J Bench Mark 1.0
buffer size 8kb
Data size 10mb
Write : 5.27mb
read 12.72

@CKHong,

better you just partition it before flashing radio and ROM
no need to see the system space going from 65 to 135.
Straight all goes to ext partition and getting 135 at 1st boot!