Think of it more as a really big water change that ends up with more water in the tank than you started with.
What I would suggest though, is if you could, set up the new tank on its own and take time enough with it to plant it and scape it as you please. Also, add into the tank at least some of the old water. And I'd probably add all the old plants into the tank before adding the fish, just to stress the fish out less.
Also, you'd probably want to upgrade your lighting to something that fits the new tank, and have said light give as much light as your previous one did...that way you wouldn't be loosing too much (although do expect some melting on the plants from being moved, but nothing will completely die back if you do things correctly, at least it shouldn't completely die back)
I also recommend...if changing tanks...consider doing something different, ya know? I find it boring to keep re-creating the same style and feel over and over again