I've played with quite a few ring flights. These are some of my favorites...
Departure - I was in love with this when I first got it. It's silent, easy to carry, practical, reliable. Everything you want in a ring flight. Unfortunately the gimmick just isn't tough enough. After I went through two I called it quits on this one. Great effect, but the gimmick just doesn't hold up well enough.
Northbound - By Sean Fields. I've gotten reactions with this so big I had to stop performing because I knew I couldn't go stronger. It requires a little simple set-up, but it's worth it. Very practical and very strong. Probably my favorite ring flight. If you get this shoot me a PM and I'll give you some tips and handling ideas I've come up with since I started performing it.
Ring Thing - Plays like a ring flight. A very brief, quick one. This is one of my all-time favorite effects. I perform this all the time. If you aren't performing this I highly recommend you checking it out. Totally impromptu. Garrett Thomas is awesome.
Hope this helped. Happy Magic!