I have TONS of Disney movies on tape, they predate my kids by years. At that time they'd only sell them for 6 months and then said they wouldn't release them again for another 7-10 years. Of course, now we have little kids and a DVD player on each TV & they're readily available. And I've upgraded to DVDs. I still hang on to the tapes because the kids can do them theirselves; I won't let them touch the DVDs yet.
I plan on hanging on to the DVDs because now my kids watch all the old tapes at my mom's house. It'll also help when friends/neighbors come over with littler kids when mine get older. However, it is then that I plan on donating my tapes either to the women's shelter or to the public library. Either way, I'll get a tax write off (a whole $1 per tape) and someone else will get to enjoy them.