Finder and programs destabilize frequently

Well, the question was answered more or less in my last thread: https://discussions.apple.com/thread/4551546?answerId=20435075022#20435075022

Meaning, I'm able to boot up normally again. However, the symptoms I was experiencing before I was unable to boot are still occurring.

Applications will frequently beachball my cursor and never recover without a forcequit. The finder often crashes, only now instead of procedurally locking up my entire machine, I can thankfully delay the inevitable by relaunching (previously, I would relaunch the finder and it would never return, and I could not forecequit apps).

I've performed a full defrag (iDefrag), I've done a file directory rebuilt (DiskWarrior), I've performed many of the tasks in TechTool and repaired permissions with DiskUtility, and I've flushed all the caches I feel comfortable doing with OnyX, and I rebuilt my spotlight catalog because I thought spotlight searches were crashing.

The only clue as to a trigger I have so far is iDVD crashes almost expectantly, and my typical Finder freeze occurs upon QuickLooking an item.