Sometimes the best sites--price-wise--aren't always the ones that get you points. I usually shop through PlayCentric or DeepDiscountDVD. I often find coupon codes for PlayCentric. And DDDVD often has the best prices and free shipping. In the longrun I make out better by saving a few bucks upfront. Another one to try (that does get you points) might be Buy.com. Or even Circuit City.
What I usually do is look at the points needed per dollar of redemption received and see what site is best, after I figure out which merchant is offering the best price for what I want. I ordered a DVD player through Circuit City because MyPoints is giving 3pts/$ right now there (a VERY expensive DVD player, but there was a special T-day promo). Plus the bonus points I will hopefully get in February. Once I get my points for shopping, it will have been worth about $8.57 assuming a 1400pts/$10 cashout level. Without the 3pts/$ at Circuit City (most myPoints sites are 2pts/$), eBates and Greenpoints were also looking good. But that's just based on what I would cashout for.
To see what sites reward for each program, checkout
http://www.sdrawer.com . But you might want to double-check at the actual reward site. The info at Sdrawer isn't always updated (like 10pts/$ at Greenpoints instead of the 20pts/$ listed and 2pts/$ for MyPoints merchants when some are offering 3pts or 4pts/$). I does require a little "leg work" on your part, and some math.
HTH somewhat!
P.S. Just as sort of an FYI, I've been looking at the Sesame Street Kids' Favorite Songs DVD for my DS.
DeepDiscountDVD = $7.80 with free shipping (but nobody rewards for this site)
Circuit City = $9.99 with free shipping
Overstock.com = $9.39 plus $1.40 shipping
PlayCentric = $10.44 with coupon code, but $2.99-$3.99 shipping
Buy.com = $11.57 with free shipping if you spend over $25 otherwise $1.90