See if the Disk is issuing any S.M.A.R.T errors in Disk Utility...
Open Activity Monitor in Applications>Utilities, select All Processes & sort on CPU%, any indications there?
How much RAM & free space do you have also, click on the Memory & Disk Usage Tabs.
Open Console in Utilities & see if there are any clues or repeating messages when this happens.
In the Memory tab, are there a lot of Pageouts?
I let this thread die because I was a bit busy, and ultimately paid the only reputable third part repair place in NYC to take a look.
1) HW tests on IO on the hard drive came back horrible. I asked the techs to replace the drive.
2) During the repair, senior level techs told me that there was a "known issue" with the SATA cables in these models...Sound familiar to anyone?
Was fine for two months, and now the problem is happening again. Good times.
Haven't changed software. Only difference is a newer version of VLC.