Guesses for linux on a moderately old laptop

https://www.linux.com/news/how-choose-linux-distro-your-old-pc

https://www.linux.com/news/best-lightweight-linux-distros-2017

http://www.linux.org/threads/which-distro-is-right-for-me.4834/

http://www.makeuseof.com/tag/6-lightweight-linux-distributions-give-pc-lease-life/

Given the information you have provided I believe many (if not all) linux distros will work great with the hardware you described.

If you are familiar with debian based systems (ubuntu is a debian based system) then stick with a debian based system such as Ubuntu. If you are not satisfied with the performance of their native graphical interface (I think it's called Unity) then look into there lightweight projects that run XFCE, LXDE, MATE, or KDE.

If the system is a spare computer that doesn't need to be used for essential task I recommend using multiple linux distros (or even multiple linux GUIs) to try them out. Honestly, your hardware isn't an issue so pick something you like and go with it.

Good luck.