iPad dock

Instead of purchasing a new TV, I'm looking to get a dock so I can watch my apps and movies in my office and listen to music.

I was just wondering, what's a good dock for the iPad that can be plugged into an outlet so the iPad is constantly charged? I'd also like the dock to have speakers, if there's anything out there that would sound better than the iPad speakers themselves. Looking to spend no more than $150.

Any help is appreciated. Thanks