Doriath, the doom weaver.

I don't really agreed with the concept of Doriath itself being "jinxed". Rather, I've always believed that the comings of Beren and Turin were not cursed, so much as they set events into motion which led to their eventual dooms. For example, if Turin had never came to Doriath, he would not have caused the death of Saeros and would not have become an out-law, etc. Likewise, if Beren hadn't come to Doriath, he wouldn't have fallen in love with Luthien, and sought for the Silmaril, and all then the ramifications thereof would not have come to pass. I think that the arrival in Doriath was a pivotal point in the lives of several different characters, and that they were not so much cursed by the place as their lives and actions after that point led towards a certain end/doom/fate.