I'll certainly agree about the need to decant so as not to drink gritty sediment, I will add another view on whether decanting red wines improves their taste.
For an article on this, check : http://www.moodysweeklywinereview.com/store/custom.html?id=254
Basically, this article talks about an experiment performed by some of the big names in wine (Mondavi, Zrali, others) 30 years ago. They took 3 big name bottles, and in blind tasting compared directly from the bottle, wine decanted then directly served, and wine decanted for an hour, then served). This was done with 3 different types of wine, and in each case - both the older and younger bottles - the wine poured directly from the bottle was the preferred wine.
I still decant, half the time for the fun of it, but there's the other side to think about - maybe it can make the wine worse!