speakers or headest

I prefer using my speaker setup, but it's not always a viable option.

I'd recommend getting some decent speakers for when you are playing solo or a single-player game and get a nice headset for when you are playing online games with some friends.

As someone said already, prolonged use of a headset at loud volumes CAN (won't always) lead to hearing loss. It's better to do what you can to avoid hearing loss, and besides, headsets get hot and sweaty in the summer.

Get both if you can.