If you want something lightweight and based off of Ubuntu, go with Xubuntu. It's more like Windows 95. I do not think it's the trendiest but it's been a stable workhorse for software development. Xubuntu is fast on older machines and virtual machines. I was turned off by the main Ubuntu distro a while ago as it baked Amazon search and other commercial offerings into the desktop environment. (I don't fault them for trying to make money but it should have been opt-in)