It seems to me that many of the responses on this thread are perhaps not properly emphasizing one of the greatest benefits of the Capital One Venture promotion -- its extreme flexibility and relative independence of what exactly you're spending money on (other than that it is with a travel merchant). You do want to be sure to direct enough of your travel spending here to use up your promotional points (and remember that spending itself earns 2% also), preferably before the annual fee of the second year is billed. But IMO, exactly which subset of your travel spending you direct here only matters insofar as whether that spending might have earned you more elsewhere.

For example, suppose in general you spend a lot of money on travel, but you know you need to spend $1,000 on Southwest tickets, and you have both the Capital One Venture card and one of the Chase Southwest Visa cards. If you spend the $1,000 on the Capital One Venture card, that earns you 2,000 points, good for a further $20.00 rebate on future travel expenses to this card. If you spend the $1,000 on the Chase Southwest Visa card instead, you earn 2,000 Rapid Rewards 2.0 points, good for $33.40 rebate specifically against additional Southwest Wanna-Get-Away fares in the future. If you expect plenty of other travel expenses in general in the future, and also expect plenty of Southwest travel expenses specifically in the future, then you'd want to direct the Southwest spending to the Chase Southwest Visa card.

Whether the $1,000 in Southwest tickets was a "good deal" or not doesn't really matter AS LONG AS YOU HAD DECIDED YOU WERE GOING TO HAVE TO MAKE THAT PURCHASE. You may feel very differently about the "value" you got if you were able to spend the $1,000 on 10 round trip tickets to your favorite vacation destination versus on a single last-minute family medical emergency trip. But the net impact on your wallet remains exactly the same.

Or take the jetBlue All-You-Can-Jet pass as an example. Suppose jetBlue offers it again this year for $500, and you buy two for $1,000 total. Because you have the time and the inclination, you use the passes to the max and get what you feel is $10,000 "worth" of travel out of it. You also have have to make a non-business trip this year where you are furious that you have to spend $500 per night for a 2-night hotel stay in a crummy hotel property because there's a college football game that weekend and alumni fans had nearly filled all of the hotels. You certainly don't feel like you got $1,000 "worth" out of your hotel stay. But assuming you don't carry a jetBlue-affiliated credit card or a credit card affiliated with that hotel, whether you direct the $1,000 in jetBlue spending or the $1,000 in hotel spending to your Capital One Venture card doesn't affect the net impact on your wallet -- Capital One will rebate either purchase, leaving you to pay for the other purchase. Again, the subjective value of your spending doesn't matter so long as you had decided you were going to have to spend.