My camera has a stitch mode. When I use that it shows the previous picture to the right or left of the display so you can make sure you don't leave gaps, and it fixes the lighting settings so they are all the same.
I use the stitch mode to guide me all the time. it also gives you just the right amount of overlap.
Photoshop HAD a very bad stitcher up until CS3 when they finally got a very good one so that's what I use now but I was quite impressed with WLPG's panorama maker. I've never even heard of Image Composite Editor.
The key to getting good panoramas is to always keep on the same plane and make sure that they don't vary wildly in contrast.
I've found that making 2 or 3 photo stitches is more useful than using a wide angle lens when you're shooting landscapes.