Absolutely worth it. I got a Anker® SlimTalk 3200mAh Portable Power Bank Backup for about $24 on Amazon and it was so worth it knowing you could use the phone for pictures, wait times, etc and not have to worry about battery life.
I just this week bought an Enercell on clearance at Radio Shack for my Android phone because it won't make it through the day... I love to check in on Facebook and post photos. We also use the touringplans.com lines app, so need juice!!!