yes this happens all the time with droids, it will not stop locking up untill u get a new phone
And the $1,000,000 question: why haven't you got a new phone yet, then?
the solution is to turn off the auto-restore feature of froyo, then wipe the device, then DO NOT sign back into your google account on first boot until you go back in and turn off the auto restore (since it defaults to on). After that, you can go back to the accounts page in settings, and log into your google account. All of your market purchases will be there, but you will have to download them manually. However, if the problem is caused by wierd leftover data in the update process, it will solve the problem.