Their are a number of brands and what system is best depends on your goals and budget. Where are you located?
I work for an AV company based on Long Island NY. We have been in business since 1969. Personally I'd recommend either hai or RTI depending on the goals for the system. With the need for lighting,hvac and audio video control RTI would be the choice. Check out
www.rticorp.com they have a great selection of inwall and handheld controls, support for iPhone, iPad and android apps as well as PC interface.
One great thing about RTI is it interfaces with other components and they just handle the control. So you can pick and choose what to integrate it with. Example Lutron is the big name for lighting control. So you can get a Lutron light system then control it from your RTI remotes and keypads. It can also handle audio, video, security, sprinklers, pool/spa, hvac, and anything else you need to control.
And with processors that retail as low as $550 that could run a small house they are affordable and have options to fit any size home.