Is a router with NAT a good enough firewall?

[fortunefaded]

You can test out any NAT leaks here -> https://www.grc.com/x/ne.dll?bh0bkyd2

Chose Common Ports or All Service Ports option. It will report back on which ports are OPEN.

[Zelucifer]

I'm more worried about getting hacked than getting viruses. Because I leave a few ports open.

Why would anyone hack you?? Do you have valuable information on your pc?

My guess would be not. Really the only "hacking" that's done on regular people's computers is through trojans. So don't get infected and won't get hacked.

An unprotected pc can get compromised in less then a half-hour. I'm not sure where you're getting the trojan thing from, but unless you're running in a virtual environment, you'll probably need to reformat within a day of running unprotected.