Daily Quests are a necessary part of World of Warcraft for all WOW players. It is really true if you want to level 85 for your character to be fully geared with enchantments for all pieces of gear, and with Cataclysm, you will want to do it all over again. For all of your characters, doing them is still a great source of World of Warcraft gold and reputation for your level of 85. So you will get lots of benefits by completing your Daily Quests.
First, you should know what you should do for all your Cataclysm Daily Quests. When you need to do all 25 of your daily quests in less two hours, you should know in advance what is needed from you, what you should do, when to do and where to do them. Certainly, by completing your daily quests, you will get the reputation. And the reputation will give you access to items and enchantments. So you should know what the best daily quests for your characters are.
You will get the reputation in the faction from doing the dame daily quests. If you are doing some daily quests here and some there, you will get the same reputation, and the most different is that it will take more time. So it is necessary to specialize the daily quests that you need. Most of the time, the faction you are trying to earn reputation with are all located in the same area. So you even save time as no flying is necessary.
If you want to gain some gold in Cataclysm, you can do the daily quests that not just pay the most but can do fast. Certainly, you should choose the best daily quests for your attention as some will give you more WOW gold and others will give you more reputation to your WOW power leveling.