If all you plan on doing is using bluetooth to play music from your smartphone or tablet, I would recommend one of the numerous bluetooth speakers on the market. I bought the JBL Flip on sale for under $90, though it's normally around $100. Compact, good battery life, and great sound. It and my phone have totally replaced the old garage radio.
I also have read decent things about the Bose Soundlink. Main drawback is the extra $30 and it seemed a little less rugged than the one I bought when I was messing with it in store.