With an average November maximum temperature of 65 degrees and an average minimum temperature of 40 degrees (and a mean of 53), you'll definitely want to bring a light jacket, plus a sweater or a heavier jacket. After all, your dates are much closer to December, when the average max is 58 and the average min is a cold 33 (with a chilly mean of chilly, especially in the wind), than they are to October, with much warmer temperatures.
If you're planning to stay primarily indoors, it's not that big a deal; a regular shirt, sweater, and light jacket will cover most situations and conditions.
But if you're planning on spending some time outdoors, for example walking up and down the Strip for any length of time, you'll want to subscribe, like the globetrotters in this office, to the "layers" school of thought when it comes to traveling. Generally, you want three layers, which you can don and shed as the temperature calls for more or less clothing.
The base layer is next to the skin, preferably a fabric that "breathes," drawing sweat away from the skin, so it can evaporate and cool you without making you feel wet and clammy; for Las Vegas conditions in late November, that would be a polyester microfiber such as Drylite -- a moisture-transferring fabric consisting of polyester (which rejects water), a hydro-nylon (which pushes water to the outside), and Spandex (for stretch and a great fit) -- that automatically activates when your body heats up.
The middle insulating layer gives you warmth; in Las Vegas, any long-sleeve shirt or blouse will do, especially if you've got wicking fabric between you and and it.
And finally, there's the outer layer, usually a windproof (important in windy Las Vegas) and waterproof (less important, though it can and does rain in November) jacket.
If it's cold out, you'll be glad for your layered breathability, warmth, and element-protection. If you're lucky and it's balmier, you can strip down one or two layers till you're comfortable.
