Update as of 11/22/12: Because this post is 9 months old and Facebook has made several changes since then, these fixes may not work for you.
If you are having troubles with posts not showing up on in your Newsfeed you can follow these simple instructions that will allow all posts to show up:
At the top of your Home page click Most Recent, then click the down arrow next to Most Recent and click Edit Options.
A box will pop up and you will have a choice to Show posts from: All of your friends and pages or Friends and pages you interact with most. If you want to receive all posts yet you do not normally interact with the page (commenting on posts or Liking posts), you will need to choose the first option. If you choose the 2nd option your Newsfeed will only show posts from pages you interact (comment and Like posts) with most.
If you have any questions please feel free to email me via my contact page or leave a comment below!