|I'd consider ntbackup to move, 12 hours??|
I'd use perfmon to see what is going on before I did anything.
The only issue with an image is you may have to fix it with drivers or boot order or such. Many people love images. I am still kind of fond of ntbackup.
"Best Practices", Event viewer, host file, perfmon, antivirus, anti-spyware, Live CD's, backups, are in my top 10