Although the company has said they have not seen any increase in fraudulent activity, they will be forcing a password change to all users later today. You can of course go ahead and change your password now. Also, if you use the same password on eBay as ANY other site, change that as well. It doesn't take much for the hacker to try your email and password on another site. I again stress that you should be using a password manager such as LastPass.
eBay has said that users PayPal (its sister company) data is safe and is stored encrypted in a completely different database on different network.
For more information, see the complete blog on eBay.