Many people, myself included believe that secondary is unnecessary. However, the reasons for/against secondary some often exaggerated.
Racking to secondary doesn't keep the yeast from "finishing up" The yeast that is actively continuing to process stuff in the beer is the yeast that is still suspended in the beer. The yeast that is left behind is mostly doing nothing anyway. It's the yeast most likely to cause off-flavors, though that's not a concern for most people nowadays if they use healthy yeast, pitch enough of it, and ferment at proper temps.
Racking also doesn't mean a greater chance of infection. Well, not a risk great enough to not use a secondary. Secondaries, have been used for centuries without problem. The beer is even less conducive to infection AFTER primary, when the alcohol level is up and the pH is down. Also consider that many breweries ferment clean beers using open fermentors. With care and the proper setup, you can even rack to a secondary with no exposure to outside air, if you wish.
For myself, I consider a secondary to be a matter of choice. It's not strictly necessary, but the downside is also minimal enough to make it a even out. I some use a secondary, and other times I simply rack to my keg. If I know I'm going to bottle a beer, I use a secondary. I find I get less stuff in the bottling bucket that way. If you are able to consistently lift your fermentor high enough to transfer your beer without stirring it up, or careful enough to siphon without sucking up a bunch of gunk, then by all means, don't fret about an extended primary.
If you are dealing with a beer that is going to be "aged", then you may consider a secondary that limits headspace, or can be purged with CO2 and sealed positively. I ferment in buckets right now and though I love them for primary, I wouldn't want my beer sitting in them for a couple of months if I had a carboy of some sort (plastic or glass).
I recommend doing whatever makes you most comfortable. If you think bacteria are sitting there waiting for you to open the lid on your fermentor so they can jump in and ruin your beer, maybe try an extended primary. If you take a RDWHAHB approach, then do a secondary. It's all good, baby!