Downloading updates while installing Ubuntu 14.04

Thread moved to Installation & Upgrades.

Best to click neither to be on the safest side. Neither is necessary. Ticking one or both can sometimes cause issues. You can update once you've installed and then install any drivers you need.

Main aim is to end up with a stable install at the end of the process. Installing third-party drivers during install may destabilise the system in unpredictable ways.

Once you know you've installed successfully, you can do an update via the Software Updater or via a terminal. Once you know that is all good and stable, you can start to experiment with any required drivers, unless you've been forced to do that prior.

One question, curiousity only: Why 14.04 LTS? Nothing wrong with it. Great, stable, solid. But 16.04 LTS was released about two or three weeks ago and is support for a couple more years than 14.04 LTS. You are waiting for the bugs to be fixed with 16.04?