Here's my experience with bottling:
3 week primary/secondary: Bottles take 4 days to carbonate, but 3 additional weeks to clear and taste good.
6 week primary/secondary: Bottles take two weeks to carbonate, and at the same time clear quite nicely.
The short primary/secondary is great for leaving a ton of viable yeast in suspension. This shortens the amount of time for adequate carbonation. However, it leaves quite a layer of yeast in the bottle and takes an additonal 2 weeks to really clear up. On the other hand, a longer primary/secondary is great for clear beer but doesn't have quite so much yeast in suspension. Therefore, it takes a bit longer to carbonate. Either way, for bottling I've found the "3 weeks @ 70 degrees" mantra to be very effective. Do this either way. If you want semi-clear beer, primary for 2-3 weeks. If you want VERY clear beer primary/secondary for 6-8 weeks.