Well, you could contribute some things to the Mudcat auction [grin]!
Don't give records to your local public library unless you _know_ what their weeding policy is. Many libraries weed straight into the trash can. An academic library is better, but find out how they treat the collection they've already got.
There are places on the web like World Wide Wax which might even give you money (or get you money) for some of them. And there are some used record stores which are also happy to take your records.
My rule of thumb in weeding my personal collections is "how often do I think of this?" and "Can I find it if I suddenly find myself fretful with wanting to listen to it? (or read it, for books)." Stuff with a high sentimental value I keep, too. Low use, easily accessible, low sentiment items can go.
Another way of handling it is finding a fellow packrat who is still in the acquisition phase of life, and asking them if they will be the life-custodian of your collection so long as they get it in the will. Must be a good friend or a relative, and put the agreement in writing, of course!
Of course, I live in a four bedroom apartment myself, and you'd be appalled --- er, astonished at how much stuff you can cram into one! Wall space may be at a premium, however!
(still in the acquisition phase, myself, mostly...)