There's one big advantage of using the built in password manager of your browser: You will immediately see when you're on a phishing site, because the login data is not auto-completed. Saved me a bunch of times.
Now, I know a centralized solution for keeping all your passwords might not be the most secure, but I think it could be more secure than having to fill in all your passwords yourself. Think about it, keyloggers won't be able to record your login data, since you don't have to type it. You can set a secure masterpassword (on Firefox at least) and that will keep your entire password database encrypted.
On the one hand it's a single point of failure, on the other hand it could actually prevent certain forms of malware to get access to your passwords.
Just posting this to get a discussion going and to possibly help prevent people from getting phished.