My best interview ever was just meeting for coffee with my future manager and having a conversation about software development.
I've been lucky I have been able to build up my network via conferences and user groups and twitter. The last time I looked for a job, all the conversations were more or less personality based over tech based.
Getting the chance to talk about different things in a more natural environment is a lot simpler for everyone involved.
Of course there are downsides too, but these are the kind of interviews I prefer the most.
(In fact the past two interviews I had also involved me bringing my child, just to make things even more unpredictable! )
And the thing is - it's actually pretty easy to tell where the other party is at, skill-wise. As in, within 10 minutes or so usually.