1. Ubuntu-- I have it installed on my Dell 1501 AMD Duel-Core 1900, it runs great, and it is reliable. I have used it for about 6 months, no crashes. Now I have tinkered with it and broke it...and did reinstall it, but i was by my doing...if I would leave well enough alone, it would be fine.
2. Centos- I have used this on the same laptop for over 2 years, it ran great, no issues...but I am much better with yum, then apt-get, so I can manage it.
3. My wife, my in-laws all have Linux based systems on their computers I built, and if my In-laws can handle linux, anybody can.
BTW, in over 3 years in moving away from Windows, I have not had any issues with identity theft, hacking, etc....my home is completely windows free...now my children use a mac, I have a Mac at home for them and simplicity of learning one system that is used in thier school district. This being said, when the Mac dies, it will be Linux from here on out.
I think Linux has a bright future, however there is a couple of issues that have not been solved.
1. major software companies working with Linux to make it compatible.
2. To many varieties, thus alot of energy disbursed over mutiple distros, rather than a few...I like Linux Mint, Ubuntu, Fedora, Centos, I tried Open Susie, I liked it but it didn't play well with my video card in the laptop, and I have not learned the command line terminology for Terminal in Susie to feel confident I could resolve the issue.
This is a rambling message, but the message is clear, Linux needs to focus on the end user, and desktop experiance. It needs to get professors to teach classes at local colleges, Community - Ed programs. It needs to mainstream and show off the benefits, which is a safe, reliable, and secure computing experiance, that is for the most part free.