To answer this properly you have to agree what is a) a new tune, b) what is impact and c) what is influence.
Joan has already made the point very well on what is 'new'
The case could be made that whatever Eddie Edmundson chooses to 'break' at 'Soul In The Sun' has an instant impact / influence in terms of audience not only as some of them DJ at local dos but also as they are punters all over the country and so both seek and play these tunes everywhere.
In one sense that makes him the most influential DJ today.
I sense that isn't where the question was aimed and would find it hard personally to waver from the Andy Dyson, Butch and Sam Sam trio. But most of us are at least trying to find the next big thing aren't we?
I can't pay thousands or even the high hundreds for records really but finding a bargain usually means finding stuff few people are looking for or even know.
As hard as that is; its simple compared to getting it exposed to the right audience with enough frequency to get the actual record the credit it deserves whether its a total unknown or just one thats been forgotten by most.
I'm sure most of us want the record to be appreciated and have impact in its own right rather than to bask in the reflected glory of the artists that did the work.