i have cingular in north carolina...we run off the 850/1900mhz band...if i were to buy a sony ericsson z600 that runs off the 900/1800/1900 band...how great would the 900 band as opposed to the 800 or 850 affect my reception in certain areas...my sony ericsson rep had one in my store the other day, and it seemed to work fine, but any thoughts on this would be appreciated...