Chase Sapphire Preferred or American Express Platinum are excellent cards to have if you fly with Alaska a lot:

1) Both have points that transfer to British Airways. BA has stupid cheap redemptions on Alaska for shorter flights. For example, I'm flying two round-trip from Seattle to Santa Rosa for 18,000 Avios. Total. That's 4,500 per person each way! Note that the AmEx transfer rate just devalued, but it's still a good deal especially when the yearly transfer sale happens (usually at the start of the year). I believe they also both transfer to Korean Air which is a good way to do longer-haul redemptions to Hawaii on Alaska.

2) CSP, at $95 a year, is a great daily use card that makes it trivial to rack up the points to transfer to BA. It also has primary rental car coverage.

3) American Express comes with Priority Pass which gets you into Alaska boardrooms. Note, however, that it's just for you. Guests cost extra ($27? $29? Something like that).

4) If you get the AmEx Business Platinum card it comes with 10 gogo inflight passes per year.

Note that having said all the above I'll be cancelling my AmEx when it's up for it's $495 annual fee renewal and switching to Citi Prestige instead. Prestige provides Priority Pass lounge access for you *and immediate family/guest*. It also has a higher airline fee rebate ($250/yr) than the AmEx platinum card. Downside is the points don't transfer to BA, but my CSP earns plenty of points for that. upside is you can redeem Prestige points as straight cash on AA flights (which will earn AS points!) for 1.6cpm.

Neil