Help me decide: Which is better, Chrome or Firefox?

Morgana

You likely won't need replacements as YouTube uses HTML5 for video(which is built-in the browser as you don't need to do anything), Flash is not needed at all (Flash used to be needed years ago but it's been mostly phased out on all of the decent websites by now). Java is likely not needed unless you got something specific that uses it. also, don't confuse Java with JavaScript as JavaScript is needed (this is not something you install as the browser just uses it unless you install a extension like 'no-script' etc. but with No-Script it will break alot of sites and basically requires manual configuration etc) but most won't need Java.

if your on Firefox you can check to see whether Flash/Java are installed or not by going to 'Add-ons' and then 'Plugins'. remove, or at least disable them if they are there. if you don't really see anything, they are not installed on Firefox.