I have come to view the use of secondary as a step that potentially introduces oxidation or contamination to my beer, and I only use it when necessary. For example, if I want to bulk age a big stout or porter, I will rack to the secondary after 3 - 4 weeks in the primary and let it sit for 1 to many months. If I am dry hopping a beer, and I can't do it in the keg, I will use a secondary. Post-ferment fruit additions are also another reason to use a secondary.
Aside from special circumstances like these, I can see no real advantage to using a secondary. The often-cited concerns regarding autolysis within a week or two of brewing are grossly over-stated, and as long as you are always pitching an appropriate amount of healthy yeast there is no concern with leaving your beer on the yeast for up to a month (possibly more). In fact, I think home brewers should be MUCH more concerned about REMOVING their beer from the yeast too quickly, which can lead to all sorts of off-flavours, like diacetyl, acetaldehyde, etc. In the latter stages of fermentation, yeast naturally clean up a lot of these compounds, so why take your beer off the yeast too quickly? Leave your beer in the primary for about 3 weeks, skip the secondary unless you need one, and I suspect you will notice an improvement in your beer.
