It depends. What I have always done is use the new mac to rip an image of the old mac using disk utility. Then I erase the new macs drive and "burn" the image to that drive. This takes a while but it effectively clones the exact same setup on your current system onto the new system. Some apps like Logic and Final cut can tell when they have been cloned (or when another mac is on the same network running that application). So it's best if you delete them from the old machine to be safe licensing-wise. Last time I did this I migrated from a Mac mini to a late 2010 Macbook pro 15". The only hitch I encountered was Logic needed to be re-authed.
I suppose you could copy your user profile over to the new machine and then use the "Users" preference pane to add it (add a user with the same exact username and password and you will be prompted to use the profile you dragged over).
But then migrating apps is a bit more involved than simply dragging the Applications folder across. There are numerous files and folders in the Library directory structure (and other places!) that would need to be replicated, exactly.
I personally would either use firewire target mode to migrate the old system image to the new one, or re-install everything from scratch to have a clean start.