My fav's are the Andis clippers. Particularily the AGC2 Model.
Here's a link: http://www.andis.com/USA/products.as...l&Animal=Horse
The blue ones on the bottom right are the best. The red one in the bottiom left is also an AGC2 and works really well.
These clippers can take alot of abuse. They're very quiet and don't burn your hand like some of the Oster's do. It's really quiet and you don't have to oil it. You can just spray it with a cooling spray when the blade gets hot. They also have a model on there that has a light on it so you can see easier. But that's not something I need.
Edit: I forgot to add that they're also compatible with the Oster blades so you wouldn't have to buy new blades.