I always tested early. I asked my husband before we started thinking about having kids (I was 20, he was 22 when we got married, so we waited a few years). I didn't want to spring it on him too early, wanted to know if he wanted to wait until I'd been to the doctor, etc. He originally said he didn't want to know until I knew 100%. (I wanted to brace myself in case we had an accident when he was unemployed for 6 months--it could have happened, but I'm very thankful it didn't!)
With our first, I wanted to wait until I'd been to my doctor to tell him, but he came home and I COULD NOT wipe the completely dopey smile off my face. Every time we made eye contact my stupid smile got bigger until I was laughing. Hard to hide that one. :) (We'd been trying for 6 months, which wasn't really long but felt like it.)
I can't remember with the second, but it was about a three weeks after he told me we could stop taking pills and let things happen when they happened. We thought it would be a few more months like our first. I think at that point I told him as soon as I had the positive test at home, but he'd been wondering since I'd been easily nauseated for a few weeks.
With our third, I took a really early test (one of those 5 days early ones) and the line was so faint you could barely make it out in strong direct sunlight. He insisted it wasn't a real positive and he wouldn't believe it until my doctor confirmed or I had another test. So I took another. And another. Each day it was darker. I never did anything terribly special, though.
Now, if I were to become pregnant NOW, with a 5 month old, 3 year old, and 4 1/2 year old, and us living in a 2 bedroom apartment...that would be special. :) I would probably just put the "I'm the Big Brother" t-shirt on the baby and wait and see what happened. And brace myself to catch a falling body.