prepaid phones in philadelphia

I was wondering what the best pre-paid plan providers are out there that any of you have had experience with for the philadelphia area(both for the city and the suburbs - I will be living in King of Prussia area for a couple of months till I move to the city in january and need a provider that will give me good reception both in and out of the city).
I was leaning towards at&t as I can get the panasonic versio phone for 69$ and I prefer that phone over the nokias that cingular uses. The phone is a very important factor and having seen and tried all my friends phones I decided that the panasonic was the one I prefered over the others. On a side note, would anyone know if the panasonic versio phone will work on any other providers plans other than at&t?

 

With verizon, your minutes are used up when people leave you voicemails (haven't seen it say that anywhere for att prepaid) and with att you can choose any phone you want also. You just have to buy it outside of att. I found the panasonic versio for 69$ on amazon.com (w/o activation) and the salesguy confirmed that it would work with prepaid.

 

and with verizon the expiration dates are as follows:
- $15 - $29.99 expires in 30 days
- $30 - $74.99 expires in 60 days