Some very good points made above.

I definitely think it's worth having both CSP (or CSR) and Platinum, as the transfer partners are different. Also, with the CSR, you can use points for airfare at 1.5 cents per point by booking through Chase, though that's not necessarily the best use for them.

You and your wife could alternate years with some of these cards -- this year you get the Platinum and your wife gets the CSR; then you cancel (unless you get a good retention offer) and you switch for the second year. Then by year two you'd have a sizable point balance between the two of you. That's assuming you can meet the minimum spends. The CSR is worth it for one year because you get the $300 travel credit twice (once each calendar year) in addition to the points. Whether it's worth it compared to the CSP after that depends on how much spending in the bonus categories you do, and whether you value the other benefits enough. Also, make sure you read the threads in the Membership Rewards forum regarding maximizing the Platinum's airline-incidentals credit, as you also get that once each calendar year (so twice in your first cardmember year unless you happen to open it on January 1).

The biggest point accumulation happens through signup bonuses. So if you can meet a bunch of minimum spends, you can get a few cards, which may translate into free flights or hotel rooms. Go for Chase cards first, as many Chase cards won't be approved if you already have 5 new cards opened in the past 24 months (the dreaded "5/24 rule"). As was mentioned above, meeting minimum spends means shifting spend (ideally non-bonused spend) to your new cards, so you have to consider whether annual fees are worth it to keep old cards that you may not use as much when opening new ones.

Seth