For my absolute favorite song, I'm going to go with "Girls Just Want To Have Fun" by Cyndi Lauper. There is just something about it that gets me up and dancing or start bobbing my head. It's really a catchy tune...so fun that it was played during the bouquet toss at my wedding and often a ring tone on my phone for all my 'girls'.
My most recent favorite is "Stuck Like Glue" by Sugarland. It really annoyed me at first, but it has gotten to me. I think seeing them live at the fair helped me like it. I'm sure this one will change in the next few months though.
And, my favorite kiddie tune is "Three Little Fishies (Itty Bitty Pool)". Super cute song that I learned when I was taking Fletcher to the library this summer. I don't always get the verses right, but he doesn't know, and he seems to enjoy it. Either that or he's laughing at my horrific singing voice. I just love when he bobs his head to music....so cute.