The old-school way is to buy a blue filter for amber light. That way, you won't get the noise from setting your temperature to Kelvin... but your shutter speed will be slower.
If you want to use flash with amber light, the flash will be white and the amber extra amber because your camera chooses 5500K. So, you should buy a color correction gel to put on your flash. It makes your flash amber so you can set a lower temperature... and you won't get the white-face-amber-background effect.
By far the best in Kelvin WB is Olympus with 2000K to 14000K... plus the One Touch White Balance function.

Every other brand does 2500K to 9900/10000K.
Canon's 30D, interestingly, stops at 2800K while the 40D can do 2500K. The 300/350/400D has a minor box that lets you adjust green/magenta in -/+3 and amber/blue in -3/+3 but it's nowhere as extreme as going to 2500K.
Sometimes, I love going to 2500K with G9 (maximum green on the Sony A700) to give a very moody cross-processed color which seems to be popular with Nikon shooters.
If I am shooting a person under amber streetlights WITH the streetlights, I keep it looking like it was amber, around 3000-3500K. So the viewer sees it and knows it's a streetlight.
But, if I am just shooting the person and not including the background, I might try 2500K to make it look like daylight color.