Share your experience!
WARNING: Here be dragons. I don't work for SE but was surprised that my Arc S came with some apps that you cannot remove without rooting your device. Seeing as internal memory space is already a bit limited I decided to root so I could run the wonderful Titanium Backup app and remove the stuff I had no interest in. I'm posting this in case others wish to do the same but I accept no liability if you remove something important and your phone crashes or won't boot. If you do screw it up then you should be able to use the PC Companion tool to restore the stock image.
FWIW I have an Xperia Arc S running the .42 firmware image.
Your mileage may vary but I went from 320MB or storage to 420MB. Any my device feels snappier and I bet my battery life is better without running extra services.
There is a more comprehensive list to be found here: http://forum.xda-developers.com/showthread.php?t=1089470
Exercise caution and if you're not sure then you can use the Freeze option in Titanium Backup to stop the app from running without deleting it.
REMEMBER TO BACK THESE APPS UP BEFORE YOU USE THE UN-INSTALL OPTION!
Great work
Do you have a direct feed of this forum into your brain uliwooly-wooly? 
totally
I have Xperia Arc. I am new and want to root my Arc. I am from India. Please clarify my doubts mentioned below (forgive me if these are silly):
1) What is adb drivers meant for? Is it automatically installed or we need to install from market?
2) Once I have rooted, Am I update the android 4.0 ICS version which will released on Jan/Mar 2012?
you can use this method to root
Please clarify my doubts mentioned below (forgive me if these are silly):
1) What is adb drivers meant for? Is it automatically installed or we need to install from market?
2) Once I have rooted, Am I update the android 4.0 ICS version which will released on Jan/Mar 2012?
I'm sorry I didn't read the whole post 
2) yes you will be able to update your phone through PCC or Update Service or OTA
1) http://developer.android.com/sdk/win-usb.html yes you do need them for that rooting method
Hello
I rooted my Sony Ericsson Arc S by following your excellent and easy to understand instuctions in order to remove some of the unwanted crap that came preloaded on the phone and in order to install the rooted version of Avast antivirus/antitheft app.
Everything has worked perfectly well for the last few months since doing this however now I am unable to update the phone via the sony ericsson update service.
Please advise
Cheers
Ian
if you unlocked the bootloader you wont be able to unless you re-lock your bootloader, take a screenshot of the error on SEUS or PCC