IPhone will not backup

Question

I have an iPhone 3Gs, 16Gb that for the past couple months won't complete a backup. Backing up, the phone prepares for backup for about 1-2 minutes then backup begins. It reaches about, maybe 10% progress in about 5 minutes then essentially freezes. I've let backups proceed overnight and they make no further progress to completing after 6-8 additional hours.
For example, this screen shot was taken after about 7 minutes of backing up:
http://i4.photobucket.com/albums/y108/Ankhanu/backupprogress1.jpg
This one was taken after another 50 minutes..
http://i4.photobucket.com/albums/y108/Ankhanu/Backupprogress2.jpg
This one was taken at just past the 2hr. mark
http://i4.photobucket.com/albums/y108/Ankhanu/backupprogress3.jpg
SOME progress was made, but it's pretty miniscule. If I let it go for several more hours, there's be almost no difference in progress.
If I cancel the backup at any point, the rest of the synch proceeds just fine, synching content (contacts, applications, music, pictures, etc) in a normal time. It just won't backup.
I've been looking for a fix for a while; I think my last successful backup was in maybe November 2009. I've come across references to certain applications causing backup issues, and to delete them; I did, with no result. I've deleted my old backups; no result. I've reset warnings, no result… I did a completely fresh install of Snow Leopard when I upgraded, and did a completely fresh install of iTunes… no change. I've tried giving the phone some hard reboots… no change.
I have seen one suggestion to delete all apps on the phone and then it will work… but this somewhat defeats the purpose of making a backup of your settings (I want to maintain my app settings)… and, well, that's a lot of deleting.
Any thoughts on how I can get a current backup of my iPhone?
iPhone 3Gs 16Gb; OS - 3.1.3
iTunes 9.1 (and prior versions back to maybe Nov.09)
System - 13" Macbook C2D 2.0; 2Gb RAM; MacOS 10.5.x through new install to 10.6.3

Answer 1

Interesting info on the cable. I am using my iPod cable... but I've also ALWAYS used my iPod cable (the cable hasn't even been taken out of the box) and it had worked just fine. I haven't encountered the other problems (freezups, etc) and it always proceeds to the backup progress, then it stops.
I have been deleting some of the extraneous apps that I really don't access that often and/or don't have any stored settings that I'll have to reset, and deleting some of the content from Good Reader to lighten the load a little on the phone. So far it hasn't helped, but I may not have deleted the right app yet; chances are it'll be one of the ones that I have to input account details into
I have another attempt in progress as I type, we'll see how it goes.
If this attempt doesn't work, I'll unwrap the synch cable that came with the phone and see if that makes a difference.