While hotel programs vary, many award hotel points based on money spent, but the airline mile option is per stay. That creates a cross-over value: below a certain spending level, take the miles; above it, take the hotel points.

Hilton, for example, offers (for now) either points & miles (the "double dip") or 1.5x points and no miles. Based on my values for AA miles and HH points, the crossover is about $300 per stay. For a one-night stay I'll double-dip. For a longer stay where the cost and points add up, I'll take the extra points bonus.

Second example: Choice Hotels gives 10 Choice Privileges points/$ or 250 miles/stay. Since a CP point is worth in the vicinity of 0.7-0.8¢ (you can get a free night at quite a few places for 6000 points, including the Clarion Claridge in Miami Beach) and 250 miles are worth $3-5 by most estimates, the crossover point is about $50. There, taking the miles hardly ever a good idea, unless you need a few for a specific purpose or place a higher-than-average value on airline miles.

[This message has been edited by Efrem (edited Mar 11, 2004).]