The first time I went to NYC, I actually didn't like it very much but the subsequent trips were awesome. I do recommend it and say go, see a show! I've seen Wicked and Mamma Mia!
I like Washington DC (which I live outside of) a lot but I think it is pretty kid friendly as there are lots of free museums and things to do with kids.
Denver and Colorado Springs are great for hiking but again, pretty kid friendly overall.
I grew up in CA and I've only been to San Francisco once (although I've been 'near it many times). I wasn't too impressed when I went and I'm not a big Northern Cali fan. I did like Monterey, CA (south of SF) a lot when I went there though. I like San Diego but that is because I'm from there. LA has some interesting points but I'm not sure I'd recommend it.
I'm not a Las Vegas fan at all.
I've been to Chicago quite a few times and I liked it but I think I'd recommend NYC over it.
Philly is interesting to visit but again, I'd recommend NYC over it.
Miami/Florida keys is fun for relaxing vacation and I have great memories there but it is also pretty kid friendly.
Asheville, NC is a nifty small town which I've been to a few times and I like a lot. If you like mountains, it is fun but Denver/Colorado springs is fun for mountains.
I absolutely love Albuquerque, NM but being in Texas, that is a shorter trip for you than me.
So I think I'd say NYC
