Ulthuan

Which Armies do you guys think are going to become the top dogs when the 8th edition rulebook comes out? Cause im pretty sick of the same old "best" top five armies.

Well, the daemons will remain tops, especially with flamers potentially getting better (one rumor is that skirmishers can shoot after marching). You will see less greater daemons, but the rest of the army is hard enough that it hardly matters.
VC will still be good, but have a few less points to throw at characters (only 50% of the army ).
Lizardmen will see lots less engines and a few of the slann may be cut back (so a 450 point Slann instead of 500+, hardly a difference), but plenty of points will still be around for scar-vets (y'know, 25% of points still can be spent on characters). Saurus with spears only get better (going from 25 strength 4 attacks to the front to what, 31?). The lizardmen will be as good as normal.
This edition can try to fix the top few armies, but generally I don't think it will. Some books will still be better than others, especially daemons.
~Grant

Dark Elves will have a huge advantage if the breath weapon rumors are true, but all of their elite infantry and assassins are taking a huge hit since they're vulnerable to step-up. The ability of Dark Elves to control the board with Harpies and Dark Riders will decrease as well, since moving regiments around will be more flexible and marchblocking/Frenzy can easily be ignored with a successful Leadership test.

I think the highelf/darkelf matchup will start to look a lot interesting when were getting rerolls vs some of their units(ASF/Init), them getting rerolls against us for hatred and majorly bloody battles when the lines clash. Our shooting might be able to wither them away, especially firing in our 2.5 ranks and with our multipurpose LSG(though not as long range).

The Hydra's will hurt with devestating breath attacks, but also receive more of hurting itself with Whitelions striking in 2 ranks and with rerolls to hit it - also with the changes to magic and Flaming Sword(s) of Rhuin apparently being a unit wide buff meaning we may be able to deal with it with more of our troops.

Methinks Chaos Dwarfs are going to be pretty good, because GW needs to sell models. If they suck, no one but the devoted few will get anything new.

well I can really say I look forward in seeing 17goblin heroes