Allow me to add to what Friesste said.
First off it doesn't so much depend on the beer as much as what you want from the beer and how much of a rush your in. Step by step; primary fermentation - should be in actually the only real fermentation, 1-3 weeks to allow full attenuation. Secondary fermentation - a conditioning step, off dead yeast and trub, allowing remaining yeast to clean up your beer and fall out of suspension. Bottle conditioning - 2-4 weeks with new fermentables resulting in carbonation and further 'clean up' of your beer.
Natural carbonation will also get you a 'nicer carbonation' smaller, finer co2 bubbles with less carbonic acid.
So generally when I brew I decide between 'quick and dirty', and 'I'm in no rush'. Quick and dirty - Ferment at the warmer end, around 70 degrees, that way fermentation is done in a week or two. Then rack into a keg with some clarifier (my new favorite is Biofine Clear) set at 12 psi and wait another week or two. Blow off sediment and enjoy, 3-4 weeks after brewing.
I'm in no rush - Cool fermentation with diacetyl rest, 3 weeks. Rack into secondary fermenter for a month. Into keg with priming sugar, for most of my beers I naturally carbonate / bottle condition in a keg, give it about a month. Hook it up, blow off sediment and enjoy, 3-4 months after brewing.
Bottle conditioning generally results in a nicer beer, I personally bottle condition most of my beers in a keg.
You can make great beers that go from primary into a keg and get force carbonated