I went through the Cohen Brown Sales Training many years ago. It was excellent. I use much of what I learned every day. In fact, I am actually now teaching my team many of the techniques that I have learned. I would highly recommend this to you without hesitation. It was intensive but well worth it!

+1 on Miller Heiman. It's good for selling to large companies where deal size is big and sales cycle is long. But it's pretty heavy. Sandler is another good one; better for smaller, less complex deals. Important thing is to understand what the role entails, who you're selling to, what's the nature of the product/service, etc. Some methodologies will be better than others depending on these things.