I own the NEX5n, the 18-55mm, and the 50mm OSS.
If you don't need fast autofocus or long lenses, I would go for the 5n. Grab the 50mm, it's great for portraits. I wouldn't go for the original 5 or 3 unless they're cheaper by 30% or more.
If you have a focus on video, get the GH2. When hacked, it meets or exceeds the 5D Mark III in terms of video quality.