What should I do with all my old tech junk?

I am currently decluttering, and I have boxes upon boxes of accumulated tech stuff (for lack of a better term). USB cables, dongles, flash drives, cameras, MP3 players, phones, installation discs, etc.

It's a giant mess that I want to be rid of, I just don't know the best way to go about it and thus have some questions:

1. What's my best course of action: Is "electronics recycling" the way to go? Should I sort it and donate the useful stuff to a thrift store? Would local mom-and-pop computer shops potentially be interested in some of it?

(Note: I have no interest in extracting money from the hoard and would be happy for the useful stuff in there to go to a "good home" that can take advantage of it.)

2. Is there anything that's simply not worth donating/recycling? Should I simply throw some older stuff (e.g. floppies, component cables, anything with a parallel port) out, or does recycling somehow reconstitute the metals/resources in them?

3. I have several dead hard drives and flash drives that have personal information on them that I was never able to wipe. Should I just hold onto these indefinitely since someone could use them maliciously, or is the likelihood of that happening close to nil?