Manjaro is good and it is possibly the next Linux I would like to try in the future. Despite that, Ubuntu is still the best distro for somebody who is looking forward to try Linux for the first time because of the large community supports and huge repository for packages.
I am using Debian for years and it is easy to contain and upgrade. If you are looking for a stable OS with a simple interface and good performance then I'd suggest Debian Jessie with XFCE.
I'm agree with this suggestion. I have tried several other distros but I liked this a lot, it is working flawlessly on any PC I have tested it, also has a very good user manual and support forum.
there is a saying "add salt according to taste" and also another saying "*nix/Linux is not user friendly because it depends on who the user is". so choosing the right OS is like dating. you may find someone extremely attractive but you can not afford to commit for a life long relationship. so my take? try as many distro as you can, start with the livecd if they have it. get your hands dirty and feet wet, go for a long drive and see how you fit in with the OS and how the OS fits in and gets along with the OS and you (the final end user) and then perhaps make a commitment. back in the late 90's we didnt have much of a choice, either redhat or debian, now you got countless OS. if you have a nerd/geek friend, then ask him/her to roll out a special distro just for you which suits your needs. let me know what you think of this suggestion.