my personal opinion is that they were both as good as each other!
tomorrow never dies was great couse it was mainly all orchestra but had some great techno like moments such as backseat driver and hamburg break out plus i love the end of the bike chase music (and the middle of the stelth fight which for the reckord is only on the special edition dvd! lol) is also another great twanging guitar moment
the world is not enough was also great couse it tookk another step forward and combinded technoised syntesised music perfectly with orchestral music! you cant tell me you dont love the end of "come in 007 your time is up" and the end of "caviar factory" and once again only on the dvd, the end credits (i ripped the music of the dvd) man i cant get enough of arnold!
im really looking forward to die aonther day... sure, only the first half is coming out at the moment, but first half is better than no half when it comes to david arnold