The four categories of computing: Desktop, laptop, netbook, tablet. This is GENERALLY speaking
Power: Desktop, laptop, tablet, netbook
Energy efficienty: tablet, netbook, laptop, desktop
portability: tablet, netbook, laptop, desktop
ergonomics: desktop, anything else
upgradability: desktop, anything else
expected life: desktop, tablet, laptop, netbook
sustainability (ability to remain on without power): netbook, tablet, laptop, desktop
consumer mobility (utility on the go for consumption, different from portability): tablet, netbook, laptop, desktop
short-term productive mobility: laptop, netbook, tablet, desktop
long-term productive mobility: netbook, laptop, tablet, desktop
Laptops only win one niche category: producing content when mobile for less than 4 hours.
Desktop. Cheaper for what you get, better performance, more upgradeable, better cooling, theoretically longer lifespan, etc. The only advantage to a laptop is portability.
Laptops have long lost the advantage of portability, and can hardly be considered portable compared to alternatives. Their only remaining advantage is the ability to fully utilize a workstation-grade operating system without constantly being plugged in.