I use ubuntu personally, so a lot of the things I love are distro-specific.
The things I personally find the most awesome:
- integrated menus. My to-do list is made with their calender/email app, then I can check off to-do items with the time/date menu. I can pause/play music, chat on a half dozen different im clients, and so forth all from standardized menus
- installing common software is absurdly easy. Use the ubuntu software center, search for software, install software. A few applications (like Dwarf Fortress) are slightly more complicated, but most apps people use are easier than most OS's. I downloaded MySQL server for my current class, and I didn't have to go to their specific website like most people would.
- included software is actually useful. On my moms new costco machine, it was installed with a lot of trial software that she just doesn't bother deleting. She then complains that she doesn't have Microsoft office, planning on buying a new license for who knows how much. Open office is included by default in Ubuntu (As well as others of course, it's pretty popular).
- easy updates. Whenever there is a security flaw found in any of my programs, a cute out-of-the-way notification tells me there are updates. One system governs all of the updates, unlike either MacOSX or Windows. I no longer get updates for chrome, itunes, microsoft, adobe, and virus-protection separately.
- fast updates. There is no standard day for patches - they come when they come. As soon as there is a patch, it is released, and the problem is fixed. They are generally open-source as well, so no secret shovelware like including safari in an update for quicktime, or some other shenanigans.
Those are the things I find awesome anyways.