About the only thing 2 nics are good for is having the internet on one and your local network on the other, then you can use a good software firewall to firewall your network.
And then your life becomes exponentially more complicated when you discover the intricacies of OS multihoming, default gateways, static routes, etc. as you try to figure out why things don't function as you thought they should.
The interesting thing is that so many vendors are pushing motherboards with two NICs, even though very few people really know how to take advantage of both, even less have true opportunities to take advantage of both, and since the motherboard vendors tend to mix Ethernet chipset vendors, it becomes more awkward or impossible to do the really cool stuff like load aggregation, balancing and failover sets if you had a switch that supported it.
Or maybe I'm just too cynical.