Aloha greenmymac,
I can empathize with you on your iPhone 3G issues. I suffered through some rather severe, albeit different, issues myself. I posted my solution on
this thread, but here are the steps I took to resolve ALL of my issues:
1. In iTunes, leave the Sync Applications checked, but UNCHECK all individual applications. This will delete the apps from your iPhone, which may take a bit of time depending on the number of apps installed. It is important to get back to only a "stock" load.
2. Once that process is complete, unmount your iPhone (eject it from within iTunes and disconnect the syncing cable). Once completed, mount your iPhone again (connect the syncing cable) and get an initial "stock" backup, which should take between 1 and 2 minutes (but probably the former).
3. Now that your iPhone has its initial "stock" backup (ie., no 3rd party apps), add those apps still available in the App Store (I wouldn't add NetShare at this time, for example) and repeat step 2. This initial "fully loaded" backup will take a bit of time, once again depending on the number of apps now installed. For example, my initial "fully loaded" backup took right around 20 minutes (I currently have 47 apps loaded).
4. Once this backup has been completed, repeat step 2 once again and your backup should be between 1 and 2 minutes only. I'm not sure, but this seems to be an incremental backup only.
It may seem overly complicated or unduly "difficult", but that's what worked for me. It may also work for you as well.
HawaiiMacAddict