Yeah, keep the famous movies off the list please. I am sure most of us movie buffs have seen em more than once atleast. Suggest something which is good but doesn't showup while googling top thriller movies.
Watched "Devil" and "Exam" recently. The former takes place almost completely in an elevator and the later in a closed Room. Both were decent, but I found Devil to be a bit more entertaining.
I would add - Anurag Kahsyap's "Shaitan" to this list. Its a very good movie -- the acting and the soundtrack is amazing! For people who've not heard it yet -- check out the Hawa Hawai song in the movie! can't stop listening to it!