I do not usually win against my many chess programs. That being said, I also do not believe that Chess programs "think". The problem with the computer is that, unlike a human, it can access every game ever played. It is like a human having access to every book ever written and every game ever played, and you have only what you can remember and tactics and strategies that you have learned. However, I play almost every day. The best program I have found is GnuChess and the engine associated with it called Phalanx. The following game was played against a weaker, but still passable, program.
Chess,MS - BRBIII [B50]
April 25, 2009
1.P-K4 P-QB4 2.N-KB3 P-Q3 3.P-QN4 PxP 4.P-Q4 N-KB3 5.B-Q3 P-K3 6.B-KN5 Q-R4 7.BxN PxB 8.N/1-Q2 P-N4 9.P-Q5 N-R3 10.N-N3 Q-R5
11.N/B-Q4 N-B2 12.Q-B3 B-K2 13.N-Q2 B-Q2 14.N/2-N3 R-QN1 15.0-0 P-KR4 16.R/B-K1 Q-R3 17.R-K3 Q-B1 18.K-B1 P-K4 19.N-KB5 BxN 20.PxB Q-R3
21.B-K4 K-Q2 22.Q-R3 P-R5 23.K-K2 Q-N3 24.R-Q1 R/N-N1 25.R-QB1 K-Q1 26.R-Q1 N-R3 27.R-KB1 B-B1 28.K-K1 B-R3 29.R-Q3 B-B5 30.B-B3 N-B4
31.R-Q1 N-R5 32.B-K2 N-B6 33.R-Q3 NxRP 34.R-R1 P-R4 35.R-B1 P-R5 36.N-Q2 N-B6 37.Q-B3 P-QR6 38.N-N3 P-R7 39.N-R1 R-N4 40.P-N3 PxP
41.RPxP B-B8 42.RxN PxR 43.QxP P-N5 44.Q-B4 Q-B4 45.QxQ PxQ 46.B-Q3 R/4-R4 47.K-K2 R-R8 48.RxR RxR 49.B-B4 B-N7 50.BxP BxN
51.P-N4 R-R7 52.P-Q6 K-K1 53.B-N3 B-Q5 54.B-R4+ K-Q1 55.K-Q3 R-N7 56.P-KB3 R-B7 57.K-K4 R-K7+ 58.K-Q5 R-K6 59.K-B6 RxP 60.K-Q5 R-B5 61.B-N3 RxNP 62.K-B6 P-K5 63.B-Q5 P-K6 0-1