Assuming you live in NYC, the price is the same for both LCD monitors if you choose free shipping from Dell. That includes paying NYC taxes.
I would get the Dell Ultra Sharp 1907FP because it has more features than the Samsumg 940BF such as USB ports. It is also more attractive looking. The Dell also has a 3 year warranty vs. 1 year for the Samsung.
Response is "slower" then the Samsung; 8ms vs. 2ms, but there is no industry standard on how to measure response time.