I say Gonzalez. Rios may have been number 1 for a short period, but Gonzalez got at least to the quarterfinals of every grand slam (with a semifinal at RG and a final at AO). Rios only got to the quarters at the USO and RG, the fourth round at wimbledon and the final of the AO, where he got destroyed by the only top 15 player he had to face all tournament. In contrast, to get to the AO final, Gonzalez beat a young Del Potro, past champion Hewitt, then-world number 5 James Blake, then he OBLITERATED Nadal and Haas, and finally lost to Federer in a very tight three-setter where he held two set points in the first set. On the other hand, Rios had 5 Masters titles, whereas Gonzalez lost the two masters series finals he disputed (to Federer in Madrid and to Nadal in Rome). Rios has 18 titles to Gonzalez's 11. Gonzalez is the only man in any sport to hold all three gold, silver and bronze olympic medals. What do you guys think?