Desktop.
Pros: faster, cheaper, easily upgradable.
Cons: not very mobile
Laptop
Pros: mobility
Cons: expensive, heat, fewer upgrade options and upgrades can be much more expensive.
Depends on how much you want to spend. You can get a nice single monitor 1080p desktop for right around $1000, but to equal that on a laptop will run you close to $2000.
Desktop.
Pros: faster, cheaper, easily upgradable.
Cons: not very mobile
Laptop
Pros: mobility
Cons: expensive, heat, fewer upgrade options and upgrades can be much more expensive.