I have several echos and I run Oregon bars and Oregon chain. One link off if I remember. The echo brand is made by Oregon I believe. I found the more standard size chain is easier to find and cheaper. And, it's the same size as the Husky 450 I run too. I use a 16" bar on both my echo 352 (different chain ) and echo 4400 and husky 450. The shorter bar does the job, and is manageable. I would recommend a shorter bar over a longer bar. Weight, sharpening, overall length, cost, controlling kickback, keeping in the limits of the saw, other stuff I forgot too.
If someone hasn't said it, hearing protection. I prefer earplugs, my dad likes muffs. Whatever he will use when no one is watching.
Best to get started on the Chainsaw Addiction right away. Seriously. An Echo 310 or whatever the new version small guy is a great way to learn, and easier to handle. And lighter, and the right tool for the job in lots of places you don't need the bigger saw.
and gloves! I like gloves, use what you like. But protect yourself where you can.