[clebio]

I have been using a Series 9 since the week it was released. It is an awesome computer. I run Windows 7 on it and use Ubuntu in VirtualBox for *nix development work. My only reservation is the SSD is only 128GB, but there's apparently a newer iteration that has 256GB: http://www.amazon.com/Samsung-NP900X3A-B02-13-3-Inch-Noteboo...

That said, I find the OP a bit unclear. If you need a computer that runs Mac OSX, your choices are clear, though fairly limited. The discussion in that case is about what form-factor you prefer (ultra-mobile, portable, desktop).

If you don't care about operating system, but are looking for a computer with a similar design aesthetic and form factor, there are several choices. The Samsung Series 9 is the closest match, in my opinion, for being metal, thin, light, and lacking a optical drive. With an optical drive, I would suggest the Toshiba Portege (R835) or so, which runs Ubuntu well.