Sockets are my favourite pro-flash feature. Flash lets you open arbitrary TCP sockets, whereas WebSockets require a HTTP-style header, so to use it with existing servers (irc?) you need to proxy everything.

I realise WebSockets does what it does for security reasons, but i do prefer Flash's method of getting around that (remote server hosts an XML policy file on a separate port) since it doesn't interfere with the connection in any way.