Landing pages are your show window
Take any shop window and break down the characteristics of it. What do you have? Essentially many components such as price, products, design etc. These gears work together to entice the passer-by to enter the shop and potentially convert.
Now imagine you could tailor the components in real time to suit the individual who presses their face against the glass of your window! If this sounds like something from blade runner, you need to think again.
Your landing page is that shop window. You have an awesome tool at your disposal. Landing pages can be instantly customised to suit rapidly changing external events or highly segmented audiences. You can constantly test and refine your landing page at no cost (apart from actual bum on seat time). Landing pages are integral to your conversions, usability and much more! They are part of the Google Adwords quality score algorithm!
Think about any shop window you have walked past. Why do you like it/hate it? Would you purchase anything from that shop? Why? These are the sorts of questions a searcher will ask when they land on your website! Do not underestimate the power of your landing page.