Anyone who uses a secondary is a SUCKER!
HA!
Ok, seriously it's really up to you. The main things to consider are:
Is the beer done fermenting?
If no, then don't do anything.
If yes, then you *could* rack to a secondary, but be sure to do it gently, and to minimize headspace and contact time with air, as this can lead to oxidation. Purge with Co2 if you can.
Or you can leave the beer in primary for a week or two to clear. If you keg, it might be fine to rack into your keg to clear, so that your keg is basically a bright tank.
The bottom line is that whether you use a secondary or not, you need to make sure the beer is done fermenting, has matured properly for the style (it varies) and is as clear as you like, before bottling.
I have been skipping secondary for most beers the past couple of years and it's been fine, but I keg, which makes it easier. Lately I've been using a secondary, mostly because I've brewed a few bigger beers and I just feel better getting the beer off the yeast cake and out of a bucket since fermentation is over. A carboy, even a plastic one, is less prone to allowing oxygen in contact with your beer. Again, minimize headspace and/or purge with CO2.