Well, it's a choice between the Devil and the Deep Blue Sea, really - but let's face it guys, these are the only two to post consistent results throughout the year in Grand Slams and Masters Series events, and they are also the only two recent Slam winners who have managed to win other titles on the Tour as well (Johansson, Costa and Sampras did nothing else of much significance either before or after their triumphs in Melbourne, Paris and New York).
Although it would be irritating, I would quite like Agassi to get there simply to see the youngest ever year-end no. 1 be knocked off the top spot by the oldest ever year-end no. 1. Plus, it would make a refreshing change to hear Hewitt described by presenters and commentators as "the world no. 2, Lleyton Hewitt".
Frankly, in the last few months it's been Agassi who's been playing like the best player in the world, not Hewitt, and he's shown that he has the ability to win the big titles more often than Hewitt - who still has only one TMS title to his name, where Agassi has notched up three in a year and has no points to defend going into Indian Wells this year.
Things could get very close indeed...