Which is the best laptop for animation and visual arts? I have heard that alienware is the best.

Hmm... well, MAC's are usually the choice of Graphic artist but if you want a PC then I would say look for a laptop designed for gaming. They should have plenty of power for animation/graphic arts.

Alienware
VoodooPC (Good but pricey)
Dell XPS

You want a fast CPU (minimum Dual Core - Quad Core would be better)
LOTS of ram - 3GB min - 4 GB would be better (but you would need VistaX64 to make use of anything over 3GB)
Good graphics card also with plenty of ram