I grew up in Syracuse and it has it fair share of Bills fans (I for one, am an example of that). Giants are the other team that people seem to like. I don's remember too many Jets fans. The Jets fanbase may be growing tho due to them having training camp at nearby SUNY Cortland.
However, what I'll never forget is when Donovan McNabb was drafted by the Eagles. So many Syracuse people jumped on the Philly bandwagon because of McNabb. It still makes me sick to this day.