Most Linux distros allow you to change there appearance dramatically, like make any menu bar anywhere on the screen. I would recommend you rather focus on getting the "best" distro instead of one thats default appearance is the most similar to OSX. Like Linux mint, Ubuntu, PClinuxOS or any other well known distro.
Then of course Ubuntu has its stuff like the exit button to the left. So it is fairly like OSX in that respect. But you would be better off with Linux mint as its basically Ubuntu with minor tweaks and added support and software, but linux mint resembles more Windows, in looks that is. You also need to take into considiration that if your used to windows, it would be better going with something that is more similar, so you feel more at home.
I really recommend you try them all out and then decide which one is best suited for your needs and comfort :Þ
Anything that uses a Gnome interface is a good jumping off point. Grab Ubuntu Lucid, install Docky and Gnome-Do, and you are pretty much covered on interface concepts. What you won't find is the quality of user experience that Mac software tends to have - really, most Linux software hovers somewhere below Windows in terms of usability (efficiency, power, and flexibility on the other hand it tends to blow all out of the water).
If you're really looking for Mac on cheap hardware you're better off going Hackintosh than Linux. Read about OSx86. You'll want to use an Intel chipset and Nvidia video to save yourself a lot of headaches getting it installed, but if you meet that basic prerequisite you can install Mac OS on your PC. It's technically against the EULA, but, eh, fuck 'em.
answered Sep 17 '10 at 10:46