I think it depends on the way you wish to redeem miles/points.

You're talking about $12,000 a year in spending. I am in a similar boat as you, spending that much a year on CCs, for my day to day and any bills I can put on CC.

For me mileage cards gain miles so slowly they almost aren't worth it for day to day. For the huge sign up bonuses sure...apply away. But think about it... you could sign up for the Continental card, receive 50,000 miles, and then it would take you another 4 years to double those miles. Or you could apply for the United card, and almost double those miles in a month.

Not that $1,000 a month is small time spending, but for gaining miles it is very slow... Unless you get aggressive, up your spending in ways like coins, etc:

Capital one would be a nice option, because you could use the points along the way for expenses. It sounds like you already have a nice little travel pattern. You'll never gain enough miles in day to day spending to pay for Hawaii and Japan trips each year with miles. But the Capital one card could knock off $250 or so in travel expenses, maybe a dinner or two, or a night or two at a hotel. Gain miles by flying your usual trips on CO or UA, apply for the CO and UA cards and get a nice big amount of miles fast.

What I do: I use my discover card whenever there are 5% cashback promotions, and my Capital one anywhere else. This has netted me $250+ in cash back this year, and not much from Capital One--yet, but I've only had the card a few months now. Signing up for CC offers along the way is by far the best way to gain big time miles from the large carriers. AA, CO have both hooked me up with enough miles to fly pretty much anywhere around the world, just by applying.