What do typical Halloweeners celebrate this time of year?

This was my question on my facebook wall a couple of days ago.  Many responded and one added I should blog on it (Jodi, you know who you are!).

I'm rather perplexed by this "holiday" and have some ideas of my own.   But, first, questions for you:

• Is Halloween a "satanic" holiday?  It its purpose to celebrate death, evil and suffering?  
• Does the origin of a holiday mean we celebrate it the same way today?  Does it matter?
  
• Is Halloween just an excuse to costume ourselves?  Is there something wrong with this?  Why this holiday?
• What's with all the candy?
• What has our culture turned Halloween into that it's become the second most lucrative holiday of the year?  Is this holiday really just a marketing ploy by large corporations?
  
• Do Americans "celebrate" Halloween?  Or are we "celebrating" something else that we just happen to call "Halloween"?

Take any or all questions or add your own question...  give me your thoughtful ideas as to what's going on here.