Enemy Unknown/Enemy Within are the latest ones & there's a mod thread on the board called the longest war (I think?) that makes it pretty much perfect. I would steer straight away from Xcom Declassified (The Bureau) as it plays out as a 3rd person shooter ala mass effect but worse. Was not a fun game compared to the other xcom's.I enjoy strategies and hadn't played any Xcom games before. Looked on steam and there's like 6+ different xcoms. Any particular one I should try first?