I'm not terribly exhausted, but I am tired. I'm still interested in all the things I was previously interested in, but I have to focus on the kid now and put those things aside until he's old enough to communicate better and isn't near as helpless.
Lastly, I don't know that he gives me inspiration so much as motivation. Previously I worked to pay the bills so my wife would be comfortable, now it's for my son and wife. If I was single, my living requirements would be far less. I'd likely have a small shack in the middle of nowhere and far fewer possessions. That being said, I love my family and my life as it stands. I wouldn't have it any other way.