Backup first… My terrible experience with XP and Norton won’t let me again run this road… 8)
NAV 2003 and 2004 are incompatible with avast! in XP SP1+ environments. Registry will be messed, you will lost protection of DOS under XP (you can test or search the forums, I posted a lot of it…).
I respect your decision, but I cannot see other reason that bad Symantec integration about your own words: I did not want to have to reinstall Winfax Talkworks as I did not want to reconfigure it, re-record my greeting messages, etc..
I use the SystemWorks, all but NAV… The only way to use a Symantec Product in my opinion. Btw, Speed Disk is one of the best disk defrag applications. NAV cannot be compared with avast in my opinion. avast rulez! 