What are my flash options like for my new NEX-6?

I started out with a 5 and then a 5n, I'm gonna get my 6 this week and have no idea where to start when it comes to flashes. The standard hotshoe means any flash will work? Should I stick to a Sony flash for any reason? Can I even use the Sony flashes or are there specific ones that I need to get?

I've been using a HVL-F20S with my 5n and have been pretty happy with it's results (aside from not being able to rotate it). It only cost me ~$100 but I get the feeling I won't be able to get the same kind of deal in this new format. I just blew a ton of cash on the 6 so I'm not exactly flush but need to get a flash for the holidays. I'd like to get one that's capable and not too expensive I guess, oh and compact would be awesome, but not a huge must.

Any guidance you fine fellows could provide would be awesome.