I have heard that Dark Elves will be strengthened in their next army list (in 2008) with an Army wide special characteristic (like the High Elf Army was with Always Strikes First).
My GW contact tells me that Dark Elves are likely to have either:-
Army wide hate, ie. they Hate all enemies and therefore can re-roll failed to hit rolls
or
All poisoned attacks and missile weapons, which means hits can wound on a 6 without recourse to the strength/toughness charts but the enemy still gets an armour and ward save.
Both of the above are major bonuses for the Dark Elves and will certainly make them more of a force to be reckoned with and a lot more popular than they are now. They are one of the rarest armys to be used in tournaments (sugesting maybe they are one of the weakest).
Note however, if you're thinking of getting a Dark Elf army your opponent is less likely to know how to deal with your tactics because they will not have faced you as much as the more popular armies like Wood Elves and Dwarfs.