Could be wrong but these have the Truvativ cranks that are on the KHS, Bianchi etc right? Someone mentioned that these have a 44mm chain line where as track hubs have 42mm chainline. With a lot of these cheaper fixies they have converted road cranks so the chainline is not perfect.

Is the cog further in than the chainring?

Some suggestions to fixing this:

i) Putting a spacer behind the cog. Not recommended but you can do it. BB spacers work.
ii) Switching cog. Some cogs esp the Surly cogs seem to have really thin shoulders so they don't line up on some hub/crank combinations. Love EAI cogs but they're pricey.
iii) Changing chains as you suggest. Some chains are just quieter than others. But if your chainline is off it probably won't help much.
iv) Oil the chain. Just for a craic to see if it helps.
v) Ride it for a while and let it bed in. Normally find it takes a little while for components to get settled.

I would also search this forum for chainline suggestions, some good info here:
http://www.bikeforums.net/showthread...ight=chainline

I would do iv & v and ride it for a little while longer to see if it gets better before messing around with chains/cogs etc.