I always stress the importance of photography and videography to my clients.  After the party has ended, your photos and videos are the only thing you will be left with other than memories of your wedding day.   Here are some things to think about when interviewing photographers:

• What type of equipment do you use? Is it professional-grade?  It's not important to get into too many specifics here, but the thing you want to know about is resolution and print size.  If a photographer is using a camera from Best Buy, the resolution may not be high enough to create the wall-size portrait that you want.
• What is your backup procedure?  Most pros will "dump" their media cards (usually similar to what is in your point-and-shoot digital camera) as soon as the wedding is over and back everything up to CD or DVD.  But what happens from there?  Is there an external hard drive backup?  Does a copy get stored off-site in case of fire, theft or other damage at the studio?
• Also regarding backups, how long are your images stored?  I was recently at an industry event where Master Photographer Susan Michal was addressing this issue - she has backups for every wedding she has ever shot.  This might seem extreme now, but what happens if your house burns down in five years?  Wouldn't it be great to know you can turn to your photographer to still have your wedding images?
• How many images are edited?  If your photographer gives you a CD or DVD as part of your package, find out if these images are edited for color correction, etc.
• Can I see images from an entire wedding?  Often a photographer might show you an album with one or two of the best images from several weddings - ask to log in to their online proofing website to see a full wedding.
• What are your emergency procedures?  Do you have backup equipment?  Do you bring it with you?  What if something happens to you on the wedding day, can you send another photographer?