Well, there are several contenders:
11. Qxh7+ (Ed. Lasker v. Thomas)
47...Bh3 (Topalov v. Shirov; this one is typically ranked No. 1 on most "greatest chess moves" lists, although nowadays some players think it's overrated and most GMs would see it quite easily.)
23...Qg3 (Levitsky v. Marshall; the Gold Coins Game)
11...Na4 & 17...Be6 (D. Byrne v. Fischer; the Game of the Century)
31. Kh2 (Short v. Timman; it's not a "brilliant" move by any stretch of the imagination, but the idea of the move itself certainly is.)
22...Rxc3 (Rotlewi v. Rubenstein)
Those were all the ones I could think of immediately. I'm sure other people have more.
Please let me know,