I too believe that coffee helps me go but quit drinking it a year ago. I managed to quit with only one headache and some fatigue but it's worth it. I sleep so much better!
I drink herbal tea and use Stevia-Plus every morning. It helps keep me regular to say the least. Stevia-Plus is a natural sweetener with fiber added to it. It is perfectly safe for IBS. You can buy Stevi-Plus in the natural food section of your grocery store.
If I eat more than usual, I will use two packets a day...otherwise I use only one a day.