I put chapter titles in my first MS. I had a lot of fun coming up with different ones, though some were hard and not that clever. Still, if an agent or publisher doesn't like them, they're easily removed. I'd say it's a matter of choice. I had what I thought were really good ideas for some, so I went with it, even if they all weren't the most amazing things I'd ever come up with. I'd say don't do it unless you really want to.