I'd say the many top players for 2004 would be:
Calibre for all the amazing work he did
Amit i shouldn't have to explain why
High Contrast for making some more high class music
Pendulum showing that they really are never going to stop pounding their mindblowing shit out
Dillinja and Lemon D because they just can't be fucked with
Photek for all the stuff waiting to drop and BALTIMORE
Bassline and Drumsound for redefining themselves and smashing it
Zinc for compiling and releasing all those slick tunes on bingo and not to mention bingo sessions, which brings me to...
Friction even though i might not like his production style as much as others, as a DJ he's got amazing skills and just blew up even more this year as far as that goes
Baron for defining his sound further and gaining a lot of noteriety
All the drum edit masters for bringing it back!
The GOOD American producers for proving there's still potential in the US
Dynamite Mc for proving you can be a drum and bass mc and make good music
Renegade Hardware gets props for the album, the remix eps, and all the other darkness
Breakbeat Kaos because its like the vip club of the scene
Full Cycle- the new peeps Clipz and Tali and all the other members had a very high quality year
Hospital for the crazy amount of talent on its roster
Ram for extending the raiders series, Sub Focus, and of course the executioner
Virus- Ed and Op had a big year, and the remixes good god
Metalheadz for reclaiming the throne
Basically it was a huge year for everyone and just goes to show that the scene is growing bigger and better, and that this music cannot be ignored.