Almost every Linux OS offers a live CD version now. I used Mint and I do not like it. On 2 laptops I had upgrade issues and program crashes. This didn't happen for these top 3 picks:
1st: the most common one: Ubuntu is pretty good and has great support for 3rd party pre-compiled packages and support for proprietary drivers (which is important for beginners who didn't select their hardware for open source compatibility). This is #1 pick because it is easy and online support is vast.
2nd: Personally, I would choose Debian over Ubuntu. It's just like Ubuntu, but it's more secure because it doesn't contact Ubuntu in the background or provide closed source binaries.
3rd: If you want top notch security, then Tails is the easiest for private browsing, encrypted emails and chats. Tails OS is great because it is actually difficult to use it in an insecurity manner.
All of these options provide a "live CD" version, so you can try before you install.