I will agree with you about ebay. Its not a good
place to sell high end items. Its mainly good for
bargain shoppers and lower end items. Unless you
are willing to take a loss, its probably not worth it.

Like a few people have already said. Anime Beta is
a good place to post sales. You will be visible to
a lot of collectors over there. The only thing is
that you will have to register to post a thread there.

Here is okay too. It doesn't get visited as much
as it used to be, but there is still a reasonable
amount of traffic. 

Most people will put up a sales/for offers page
and post the link both here and at beta.

PS I'd list series I am interested in collecting
from, but it would get too long ^_^