I agree with Chris_K. I just recently cashed in 300,000 AA miles for two One World Explorer round-the-world tickets in business class. Comparable fare - if you bought two OWE C/J class tickets, they'd be US$5500 each, so the miles come out to $.037 each. But the OWE frequent flyer redemption has different rules than a ticket you purchase (for example, we're doubling back, where as purchased ticket requires you to travel in one direction). If you added up the individual quoted fares from the different airlines for the segments we're taking, the tickets themselves would be around US$10,000 each, making the miles worth $.067. So I agree with all the posters who say that using miles for domestic travel doesn't usually pay. The exception is mid-week travel without a Saturday stay; AA, DL allow you to use miles for this whereas UA does not.

Hotel points seem to be a mixed bag, as do Amex Membership Rewards points. You almost always lose on transfers between, and few of the hotel programs (Starwood is an exception) are really all that generous with the point values. I just redeemed 50K Marriott points for 3 nights at a Renaissance...came out to $.009 per point vs. same room at quoted rate. I think using them at the hotel was a better deal than xfering to AA, where they would have become 15,000 miles.