Sorry, I forgot to come back and answer this.
So you say Debian, excelent choice.
You should use aptitude or synaptic. Aptitude is a very smart console program. Synaptic is a GUI program that does the same thing as aptitude, only it is not so smart. What I mean, synaptic is the best package manager with GUI you can get at the moment and does its job very well, but aptitude is genius.
you say for example as root in a console:
|
Source code
|
1
|
aptitude install kde
|
, and it will show you a list of things it will perform. Be carefull it does not delete some important package like python, coreutils or xorg. If everything suits you go on and it will do the job.
Ask for more on the debian forums if you don't make it, they are quite active, much more than this forgotten forum.