I Love CO!!
I grew up on the western slope in Grand Jct but haven't lived there in over a decade. We are getting ready to move back though from a year in Atlanta and I can't wait!! We also moved from Boulder when we moved out here to Atlanta and we also lived in Greeley which is in Northern CO. So here's a bit about each from my experience, FWIW

Grand Jct - desert climate, surrounded by three very different and distinct mountain chains. You have the bookcliffs which are grey and look like "dinosaur backs" are peeking out. The color isn't terribly pretty during the day but wow! when the setting sun hits them....they take on the color of the sunset. PM me your email addy if you want me to send you some very recent pics I took when we vaca'd there this Aug. The other mtn that stands to the east of the valley is the Grand Mesa and that one is full of green trees and lakes. The Colorado Nat'l Monument stands the SW of the valley and it's all red rock and again, is amazing with the setting sun. All are wonderful for hiking. GJ also has the Colorado River that flows right by so there is a lot of rafting and canoeing right there on it. The summers are really hot since it's desert and it gets up to 100 degrees. They tend to have longer summers/falls than the eastern slope and it doesn't snow as much either. After all, you aren't that far from the Utah desert. I am also unsure of how progressive the city is now. When I grew up it was extremely conservative. However, I have a friend who lives there now (recently moved from Boulder) and her fam loves it. She said it's becoming a bit more progressive.
Greeley - Will never, ever move back. Sorry if there are any Greeley lovers on this thread, no offense meant to you. It's a very conservative area, no mountains that close by, more of the prairie lands feel. It snows but it's not glam like it sounds like you are looking for.

Boulder - Ah...Boulder....my real love.

Mountains right there, easy to get to camping, hiking, mtn biking, kayaking, etc. Very progressive community, a wide variety of holistic care givers which I loved. The only thing is that housing is reallly expensive and cost of living is high as well. There aren't a LOT of things for children however but they were trying to begin adding more that appeals to fams with younger kids. People usually have to go to surrounding towns to find activities for kids if they aren't in to outdoor activities or don't want to simply go to Gymboree. There can be a LOT of snow depending on the winter and it also gets in to the 90s-high 90s during the summers. Fall and spring can be short just depending or they can be longer and lovely. CO is dry no matter where you are really though so you may find that a bit harder to adjust to.
We didn't realize how great we had it by growing up and living in CO until we moved to GA. We didn't realize that CO is actually a pretty progressive state...not THE most progressive but they do allow homebirths (Boulder has a lot of wonderful homebirth mw's and I had one myself there), allow homeschooling, having philosophical option for vaxs, etc.
Despite how I feel about CO, I have noticed though from talking to friends who have moved to Boulder from other places, that they pine for home just like I pine for CO. So you may find if you moved to CO that you end up missing TX when you didn't expect to. Or, you may fall in absolute love with it like so many others have.
HTH, good luck w/ your upcoming birth and I hope you enjoy your CO vaca next summer!!