It sounds to me like you're having issues with desktop environments rather with distributions. You seem to like lxde, so why aren't you just using that desktop environment with what ever distribution you like. If you disagree, and think that it is the distribution, tell us the issues you're having with any distro you've used or are using specifically, and we'll do our best to help.

i have on my second computer lubuntu.
Il like it because its very customizable,simple and so easy.
but if i want to install a user insterface,i make like:
apt-get install kde and it will install kde?
im a noob in these kind of distros xD

desktop environments aren't just one package. most distributions make what's called a Meta package which include all the stuff you'll need for Foo desktop environment. Meta packages sometimes get called different things. you need to check out ubuntus page that lists all its available packages. it's been a long time since I've used Ubuntu but I believe the correct syntax to install kde was,

so if i enter this in the command line at startup of debian i will got kde....
but did i need extra things after????

No, this will only work for Ubuntu and derivatives, Debian is not Ubuntu, don't mix that up. If you want kde on Debian you have to install the package kde-full.

if you enter the command I gave u into the terminal from within Ubuntu, you will be prompt for your password, and once entered, it will install kde.
adding onto what tobi has said. debian is different to Ubuntu, similar in some respects, but different. this is what I mentioned earlier; because it's a meta-package, some distros will call it different things. although there are slight differences in what you will get, debians package equivalent to 'kubuntu-desktop' is 'kde-full'. to install kde in debian, you would open your terminal, and;
(the command aptitude can be used exactly as above in place of apt-get.)
kdm will be installed with the commands I've given you, and during the install process, you will be asked which display manager to use if you already have one installed such as gdm. if you don't know what a display manager is, don't stress, choosing one or the other wont harm your system at all. if you want to know what a display manager is, Google it.

these commands will install all dependencies required by the kde desktop. once the downloading and installing has done. you have to close the terminal logout and then from the logon screen you will have to login again but before doing so, change your 'session' to kde/plasma desktop. after major changes like this to my system, I always prefer to restart my computer before booting into the changed environment, but that's just me.

it lok fine to install!
i'll take a look(debian is very lightweight) and i will give news =)!!