Has anybody noticed on their systems how high the USBPORT.SYS (USB 1.1 & 2.0 Port Driver) is on a DPC count? (Using LatencyMon)

Mine is clocking in at between 60'000 and 90'000...

I am sure this is too high....

(Win 7 64bit SP 1)

Between 60,000 and 90,000 what?
 
It would depend on what you have connected to your USB ports, it's normal that it's one of the highest in the list of DPC's especially if you have a USB interface.
 
Are you actually suffering drop-outs, clicks or pops in your audio, or unable to get your RTL low enough?
 
These things are only worth sweating if you've got a problem.  If you have try removing anything non-essential from your USB ports and see if there is an improvement.
 
Many people get hung up on DPC figures when there is no reason to, some taking it to the lengths of a competition to get the lowest numbers...lol.  DPC figures are mostly important when trying to troubleshoot and eliminate an issue, if you don't have an issue don't sweat it. 
  
 

Nothing connected to the USB ports at all.

Been monitoring for 35 mins and the DPC count is now 1938500 which is considerably higher than anything else.

No pops, clicks, latency issues.....

[I am trying to get to the bottom of my random Sonar crashes from this thread.... (Which I know will be MAudio drivers related anyway as Sonar reports a 0xc0000005)]