The two universal currencies out there (that I use) for reward points are American Express Membership Reward Points and Chase Ultimate Reward Points. More about the two can be found on many sites.
You have to learn about the hotel, airline, credit card cliques. We have two main players: American Express and, J.P. Morgan Chase. Some of the big partners with American Express are SPG, ANA, Delta and British airways. On the other side Chase has relations with Marriott, Ritz Carlton, and United airlines. So it may appear that you have to be loyal to one point system vs the other. This is not the case. For example If you wanted to fly on united from Tokyo to Guam, you have the option of booking a flight through ANA Milage Club using American express points:
It will cost you a mere 10,400 yen in taxes and 20,000 ANA Miles (moved from amex points at a 1:1 ratio)
If you book with Chase ultimate reward points you can get the exact same flight for 25,000 MP points (25,000 Chase UR points at a 1:1 ratio) but paying only $33.60 in taxes.
Another example is direct flight from SFO to Tokyo Haneda:
On United they want 70,000 UR points as MP points and $43.80
Surprisingly the same flight on ANA is only 50,000 AmEx Points for 50,000 ANA miles at a 1:1 ratio and 26,890 yen in taxes.
Its all about code sharing. The flight is on a plane that says United (united metal) on the side, but it carries two flight numbers, one for ANA and one for UAL. Lets look at the other side of the coin here on an ANA metal flight using United miles:
On United they want 70,000 UR points as MP points and $44.10 in taxes to fly ANA metal
Again, the same flight on ANA is only 50,000 AmEx Points for 50,000 ANA miles at a 1:1 ratio and 31,530 yen in taxes.
To sum it up:
|UR Point||United Tax||MR Point||ANA Tax|
Keep two piles of points, because one may be more valuable than the other depending on route!
Additionally JAL has a route out of Tokyo Haneda of which you can use AA miles or JAL miles. Best thing is you can transfer AmEx points to BA miles and book that way as well.
35,000 JAL miles with 31,490 yen with JAL
50,000 avios and $262 using British airways miles moved from AmEx
or $1,539.50 with american airlines of which you need to call to use AA miles to book.
Or you cold even use 60,000 asia miles moved from Amex.
So it may be not easy to book JAL with amex, but certainly there is a bennifit to use AA miles to book JAL. Check out this one post about how I used BA miles from Amex for Japan flights.