my strategy has been to do the following:

1) research who partners with who...

2) figure out what you fly or can fly and how that works with your miles or airlines you like...

3) bring up those that work to levels you can later use when you really need to use them. For example, if I had 3k on US Air, I might just use those for magazines. If I had 3k on AA I might bring it up to 5k and transfer to HHilton. But if I had 69k on United and didn't mind flying econ, I would try to get 1,000 more miles to bring my account to an even 70k and fly two people to Hawaii.

I would tend to bring my miles up to no lower than 35k levels if you can do that over time. That way it is worth using them on trips to places like the carribean or hawaii. I then stop concentrating altogether on airlines that I have like NOTHING left in anymore and just worry about the ones I still have growth in.

I have many AA, UAL, Singapore Airlines, BA, Alaska, and NWA right now. I have HHilton too and some Starwood, but everything else in my world is kind of minor these days. Thus, less to concentrate on, and if you really look closely at who is in all the partnerships and how, you can see that I have many options using the above.

I say you should quickly grow your accounts up to levels you like and need, and then BURN EM when you need to! I think it's all going to change too much from the ways we like it to be some day soon anyway. Getting less worth it all... Especially for those who fly less or have less miles in their accounts. I am one of those as I do mostly leisure travel and don't mind flying econ alot, but I do have flying and travel experience, which some of the big guns in here may not always understand how...

Make it so if you HAD to suddenly choose to use an award, you are in a position where you CAN. Mine are all at or just above an even 5k level in that sense... (for example, 35k or 36k, not 34k.) that way you do not need to buy or wait for miles.