What's in a name?

I have a feeling this is going to turn into mostly a baby blog. Sorry if that is boring for some of you. We won't find out the gender for a couple more weeks but it's never too early to start thinking of names...

If it's a boy:
We've had a boy name picked out since before we were even married. We want to name our first son Nathan James. I love the name Nathan and I love that it means "gift from God." I also love having the middle name James because he'll be named after his daddy, Jim is already a jr. though so we didn't want to use James as the first name.
Another boy name I like is Matthew. That is Jim and his Dad's middle name and I would love to use it as a first name for one of our sons.

If it's a girl:
This is a lot harder. I have tons of names I like but I don't know if I would really name my daughter any of them. It's a lot harder for us to agree on girl's names so if it's a girl, she may not have a name for awhile. Also the middle name has to be Julie or Julia because it's a family tradition for 3-4 generations on my mom's side and I have to keep it.

Here are some names we've thought about....
Alyssa-I used to love this and Jim really likes it too, lately though I don't love it so much
Brooklyn-I think this name is so cute. Jim thinks it's weird to name her after a city. He decided though he could live with it if he could call her Bronx Bomber as a nickname and buy her a little Yankees baseball outfit:)
Madeline (Madalyn, Madelyn?)-Can't come up with a spelling I like for this one

Other names I like but probably won't use for one reason or another: Kaitlyn, Lauren, Alexa (Lexie), Savannah, and Emma

Any ideas? Which do you like?