1. One may not kindle the Chanukah lights higher than twenty Amos from the ground.
2. The Chanukah lights must be placed within one Tefach of the doorway.
3. One may not count money next to the Chanukah lights.
4. Rabah always ruled like Rav when he argued with Shmuel, except for in three exceptional cases where Shmuel was lenient.
5. One may not kindle the Chanukah light while holding it and then put it down after it is lit.
A BIT MORE
1. This is because people do not notice things so high up. Since one of the main purposes of the Chanukah lights is to publicize the miracle that occurred, one who lights them so high up does not fulfill the Mitzvah.
2. The Gemara concludes that they should be placed on the left side of the doorway so that one is surrounded by Mitzvos, with the Mezuzah on the right side and the Chanukah lights on the left.
3. Performing a mundane activity by the light of the Chanukah candles is considered denigrating their holy purpose.
4. These cases are: Passing the light from one Chanukah candle to another, removing Tzitzis from one garment and placing it on another, and the law in the case of Davar she'Eino Miskaven.
5. This applies even according to the opinion that the Mitzvah is fulfilled by placing the Chanukah light in a certain area. Since people who see the person holding the Chanukah light will assume that he is holding an ordinary candle, the element of display of the miracle is lacking. (See #1 above.)