OS X (Yosemite) offline password manager
I am also a web developer and couldn't recommend 1Password more highly: https://agilebits.com/onepassword/mac

Honestly, the price has by and far been worth it for me. I believe I have ~300 login items in there and nearly all of them have different, very secure passwords. You can store nearly any data in the there and it is extremely flexible. The keyboard shortcut Command + \ automatically fills out logins and makes that part extremely easy (as long as there is a URL with that). Note that as of 1Password 5.0 it does not support auto-filling HTTP Basic Authentication. You can still copy/paste those credentials, though.

It is also possible to tag and organize items. There are many types of items including logins, servers, credit cards, identities (for filling out your name/address/email/etc.) and notes which also create a natural organization. 

Edit: I also like the fact that since the URL can be (and is) saved in 1Password for the login it will not automatically fill in a form that is not the correct URL. For example if a scammer sends you an phishing email with a link to login to your bank, 1Password won't recognize the site and hence will not automatically fill the form when you hit the keyboard shortcut. 

I will also note that 1Password offers excellent multi-device syncing. 

I have tried SplashID and my brother (who also does web development) has tried LastPass, I believe, several years ago but we both are on 1Password and love it. 

I am not affiliated with 1Password.