When you say "youtube stuff" do you mean uploading/editing videos, or loading them quickly?
CPU: If you want to create/edit/upload videos, go with the 3770k, if you're just going to be doing gaming, go with the 3570k.
Water cooling: If you have the money go with a custom water cooling loop. Buy the parts yourself (pump, res, coolant, tubing, fittings) it will look nicer, and much more customization.
Memory: If you're going to be creating/editing/uploading videos, 16 GB of RAM won't hurt. If you're just doing gaming, 8 GB is perfect.
SSD: Go with a 120 GB SSD for a boot drive. Also, if you're doing youtube video creating/editing/uploading, grab a second hard drive to record your games to.
PSU: 750 watt should be fine, 650 watt would even do but if you have the money grab a 750 watt, especially if you plan on adding another GPU in the future.
Let me know if you have any questions!