I did a fair share of painting Warhammer, so I naturally use those minis, though Rackham... the pieces are great. Not so good when you want to field a million goblins, though... they DO burden the budget quite a bit. As for colors, I strongly recommend the 'tall' acrylic colors (with a tiny opening at the top, don't dry if you just stash them for half a year), either Games Workshop game color, or the Vallejo colors, both acryl.
As for brushes, I use a 0 for the crude stuff (undercoat), a 2-0 for the finer stuff (standard brush) and a 4-0 or 5-0 for the fine stuff: ornaments, eyes, gems...
PM me if you want a hint.