Interesting thread, and interesting answers! But in reality there is no one-size-fits-all answer to the secondary question.
It is true that in the good ole days it was recommended to go fermenter to secondary for period of clearing, and that over time folks began to figure out that the risk of oxygen far outweighed the presumed benefits. So it became fashionable to drop the secondary, and now the no-secondary has become dogma. Thing is, this thought process has really become obsolete itself. Remember when the move away from secondary began most of us were fermenting in carboys, or buckets of some kind. Transfer to keg, secondary, bottling bucket whatever was done with racking cane or via spigot and gravity. There was no real way to avoid oxygen, you just minimized it. But today a good many of us are fermenting in sealed pressure capable vessels be they stainless or plastic. CO2 purging has become commonplace. CO2 transfer is the norm. And there is now no more real world "extra chance" of O2 ingress from transferring to a secondary than there is just leaving it. Not if your system is correctly assembled and you know how to use it! If you can pressure transfer to a keg for service without o2 issues, you SHOULD be able to add a step in between without issue as well. And don't forget that when you ferment a lager, then transfer to the ultimate serving vessel then store for several weeks or months to mature and clear you ARE in fact using a secondary, even if that second is also your serving vessel.
Now I see the growth of folks fermenting, carbing, and serving all from the same vessel. I will not be shocked if this is the wave of the future and becomes the norm in some fashion. And good if it does! But it will still not end or solve the secondary question for a number of reasons. There are and will remain legitimate reasons to secondary for some brewers.
While it is true that secondary is not necessary for most low to modest gravity beers, and that "fresh" IPA styles are likely best left in the primary for hop utilization reasons, there are a number of beers that may very well benefit from secondary. There are many styles that benefit from or need long term bulk aging; many RIS or Old Ale, or Barleywine styles come to mind. I know there are those who claim that leaving such beers for long term storage of many months in primary on the trub will show no issues with autolysis, or vegetal flavors. I also know many others (Myself included) who have experienced quite the opposite. This tells me that at the very least this is a hit or miss area. I for one know the frustration of building a very expensive Barleywine, and investing the time and effort into it only to have to dump it a YEAR into the process because I bought into the notion that the it would be fine all that time on the crud!!! I'll pressure transfer to a clean vessel and bulk age clean for long term beers from now on thank you! THEN there is the question is oxygen all that bad all the time? I for one do not think so, and it has been pretty well documented that some O2 character is a good thing in many really big, long aged beers. The same could be argued for things like Frambois, some lambics, some big Belgians, etc. Again, one-size-fits-all is not true for O2 and beer anymore than it is for anything else in life.
If I could I would like to add some personal anecdotal rhetoric to this: For MANY years now I have brewed a big RIS, and a Big barley wine or Old Ale on an annual basis. This goes back to the days of buckets/carboys/racking canes (In fact back to a home made bucket in a bucket mash tun!) These were always fermented for 4-6 weeks, then transferred to a secondary for bulk aging of 9-12 months in a cool dark corner. I still have many going back years and have greatly enjoyed how they change and mature over time. But a few years ago there was a blip in this rotation. The above mentioned Barley wine that i left on the trub for almost a year. The flavors that formed in that experiment are NOT something I am willing to risk again. It was awful and an awful waste. Others get away with it; good for them. I will rack and risk the O2. Which brings up the topic of just how bad or not is O2 is beers like these. Following the disaster of the Barley wine I did what so many people do - I went off the deep end the other way. I brewed my annual RIS (A take on Courage) and this time I used ALL the gizmos and tricks. I fermented in a stainless conical. I close transferred to another stainless bucket that had been purged with CO2. I bulk aged this 9 months which has become my standard with this beer. I pressure transferred to a corny for carbing. Then took the finished keg to a friends brewery where he bottled it for me on his counter pressure filling station. This batch was as O2 free and sediment free as i could get it. And of all the brews of RIS I have done going back to about 1990 when I started this annual session it has been my least favorite. It never developed the deep flavors i have come to expect and it has not aged very well (It is five year this year since bottling six since brewing ) I have gone back to some old school backwards brewing for these beers since. I have fermented the past four years in good old plastic buckets for 6 weeks, them I transferred by gravity to a sanitized keg with a mylar balloon of CO2 on the airlock. I purged the headspace on the keg a few times then bulk stored in a cool place. After 9-10 months I primed, and bottled with a bottle filler just like the stone ages and bottle conditioned everyone of them. Welcome back complex flavors and continuing maturation! (And NO they do not taste like wet cardboard or paper! I WISH cardboard and paper tasted like these old brews! I'd be chewing a big wad of it all day everyday if that was the case! Hell, that would be COOL really)
I have no doubt others have differing experiences. And that some will disparage my tastebuds! But that is ok, mine are the only ones that really matter in the end. I am equally sure there are those who have gasped and fainted at the sheer horror of an O2 molecule contacting beer! And doubtless there are folks who will wish too thrash me about the head and shoulders for even daring to suggest that some O2 might not only be OK, but even GOOD thing at times. But that's ok. I am still happy.
So you probably don't appreciate the benefits of using a secondary then? 
" doesn't really add very much, does it? Maybe some 'I haven't got a clue, to be honest'? It's not even 'Blah! Blah! Blah!' 
