I know there are a lot of Malthus adherents out there who think the last thing the world needs is another human on the planet. While Malthus' theories haven't been validated yet, there's a lot of years and people left for that to happen. At any rate, I have to say that despite his theories, I love having kids.
When I say having kids, I don't mean actually birthing them (although I am glad I'm not a woman and that I don't have to go through that whole process even with my prior assertion about childbirth/pregnancy vs. back pain), I mean actually being a parent. While our little daughter has only 2 volume settings (0 and 11) and our son doesn't understand the whole "sleep is a wonderful thing for people at night" concept, having kids is glorious. There is nothing funner than having someone run down the stairs as fast as they can and give your legs a big hug while saying "DADDY!!!" or having them look up at you without being able to say a word and try to figure out the world. Sure, kids can be frustrating and obnoxious and a lot of other things, but the good outweighs the bad by a significant margin.
Things are so much funner with kids. I love Christmas and all the other holidays, but at this age they've just become part of the landscape. It's nice leading up to them, but it's just there a lot of the time. With kids, they go mental over the smallest thing. They love looking for the eggs or stuffing 45 pieces of candy in their mouth at the same time, and isn't that what the holidays are all about (other than things like religion, family, and helping people)? I could go on repeating myself, but I'll just leave it at that. Kids are great and if you've got the right arrangement and circumstances, go ahead and have a couple. You'll never regret it.