Pidgin

In case you haven't guessed, when I say "ninja mode", I'm referring to settings that cause the instant messenger to be subtle. I know that's not very important to many people, but it is to me. I like the way Pidgin is. If you don't have any conversations open, it just has a system tray icon of a green circle. When someone IM's you, it turns into an orange rectangle. That's it. I could get bombarded with messages and shit and someone on my computer would never notice. A lot better than minimizing a window and hoping it doesn't blink lol.
Pidgin doesn't have webcam support, so that's one of the things I'm hoping to find in these instant messengers. And sometimes it seems maybe a bit slow or iffy with the connections. Especially Windows Live. Sooooo bad. But yes, overall I find this to be a great messenger. Not the MOST user-friendly thing but it is pretty easy to use, and it does support many protocols and has many plugins, although to be honest, I couldn't be fucked even TRYING to figure out how to use them. I'm sure it's simple as shit once I know how. I just....don't know how. Luckily, I don't care about plugins.