I have used a small portable PA system in my home studio for the last couple of years. It is a Fender Passport model. I have the 300 model but there are others to choose from:

http://www.fender.com/en-BB/passport/

I know that Yamaha makes a competitive series:

http://www.yamahaproaudio.com/global/en/products/pasystems/

I like the portable PA systems rather than studio monitors becauseof their portability, and their built-in small mixers make it expandable if you ever want to play outside the house to small audiences.