I have a personal account, and I also have to use it for work... so I have had a chance to dig into some of its many features... and yes, there are MANY features.
While some people don't like that Google uses all their data (what you search for, where you log in from, etc.) for marketing purposes.... others DO like the power of the application Gmail (and those it comes with... the entire "Google suite" of applications).
Anyway, here's some very neat stuff you can do just using your gmail account:
http://lifehacker.com/how-to-turn-gmail-into-your-central-productivity-hub-1626946674
As you can see, it's a link to one of my favorite websites!
Let us know if YOU have some creative things you do to make your Gmail productive for your needs.