Kind of what Euph said above, and here's a little better explanation as to why. The PRL (preferred roaming list) basically decides what cell sites you'll connect to when you're out of your home area. The key term there is "roaming": if you're in your home area, you aren't roaming, so the PRL does nothing in that circumstance.
I'm a former Alltel user too, and the current Alltel PRL you should have is 40069. Not quite sure why you have the 300xx PRL, as that was for dumbphones.
Should you have an Alltel (400xx) PRL or a Verizon (52xxx) PRL? That kind of depends on where you are. If you are still in the area you were in at the time of the takeover by Verizon, you might be better off with the Alltel PRL.
Using myself as an example: I'm in Appleton, WI, which was never a very strong Verizon territory, and all the Verizon network here is on the PCS band (1900 mHz) which does not have as good of a range as the 800 mHz band (plus in this area a much smaller footprint... there simply aren't as many Verizon towers as there are Alltel towers). So, in my case I'd be hurting myself by using the current Verizon PRL and being forced to use the Verizon towers when the old Alltel towers are more plentiful and more reliable.
This is just an example. Your area might be completely different.
