You can get DH a card whenever you want. I've read that people get an associate card for their spouses and then get their spouses a card of their own with bonus. Using Chase's UR is a great deal because you or DH can transfer miles into each other's mileage accounts.
I just started "travel hacking" when I learned about it last year through an NPR podcast. We were moving and trying to buy a house, so I didn't start until Jan. We've collected almost 400,000 miles and points so far (we're doing some work on the house and unfortunately, my problem is keeping the applications going).
I would also recommend the United Explorer card if you can get the 50k with first spend. Another great card is the US airways' card, who is a star alliance member. 40k for first spend, people get multiple with the bonus, plus you can play their grand slam in the fall and get up to 100k miles by jumping through their hoops like a circus animal. Also, they pull transunion (usually), and most other banks pull the other two, so chase won't see that inquiry.
I also recommend looking at where you want to go and how, not what your home airport is. For instance, if you just wanted to fly domestically, my father just scored a SW companion pass without stepping on a southwest plane. So now, my father and mother travel 2 for 1 (even on rewards) plus they have 100k+ points to burn through on SW. If you wanted to go to china first class, AA points are probably your best bet.
so much to learn, so little time. I also enjoy
mommy points. She isn't over the top and doing the real crazy stuff. her advice is a little more practical.