Looks like Ubuntu based on my limited experience with it; the thing at the bottom is mac-ish but I know that's available for download for both windows and linux, but that not-quite-start bar at the top looks like an OS I've used, and I've only used Ubuntu, Knoppix, and Windows XP so I'll vote Ubuntu.
And I'm not really sure I can post my desktop here; it's not that it's NSFW (which it is but I could fix that), but some of my folder names are a tad 'out there' (you know, "crap," "junk," "bull****", "more bull****", "big bull****", etc...Unique organization system but I can always find the stuff too

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