Se7en
Margin Call (even though this has completely different actors than Wall Street it was probably a better sequel to the original compared to Wall Street 2: Money Never Sleeps)
The Negotiator
And I also agree with Usual Suspects, KPax, Glengarry Glen Ross. Never seen House of Cards or Pay It Forward, but the latter is one of my mothers favorite movies. Great actor.
Actually just saw a Kevin Spacey movie last week, Midnight in the Garden of Good and Evil (1997). It was alright, he played his role well.
Actually when I saw the thread title I had an immediate fear that I was going to click onto the thread and find something similar to Philip Seymour Hoffman. I'm still upset about that.