I am new to Linux and wanted to ask which is the better choice for a first encounter: UBUNTU with Gnome or KUBUNTU with Debian? Hardware is not a question, so it does not matter if one is bulkier or slower, just with what version would i get along better coming from Windows.
Thanks
You are sort of asking the wrong question.
Both Ubuntu and Kubuntu are Debian based linux distributions.
Ubuntu uses the Gnome interface, Kubuntu uses the KDE interface.
Personally, I prefer KDE (now it has reached 4.3.0) - smooth, consistent, integrated and good looking (and probably more Windows-like). Others will say the same thing about Gnome. In fact, you can try both on the one system - you can choose to install the Kubuntu feature set onto an Ubuntu system, and make your choice of interfaces at login.
Si
I prefer Gnome, as I’ve never really liked the way KDE looks. You can install KDE on Ubuntu too by doing sudo apt-get install kubuntu-desktop at a terminal, so it isn’t really the be-all-and-end-all whichever one you choose.
I think KDE is a little more like windows, but I personally prefer Gnome over KDE for most applications. Both should work fine.
You can probably find a live CD / usb image for both to see which you prefer.
I’ve just fairly recently ditched Windows on my home PC in favour of Mint (http://linuxmint.com/). Might be worth checking out as an option if you’re switching from Windows, I’ve found the switch relatively painless. And comes in both Gnome and KDE versions (I’m using Gnome which I’ve liked so far, haven’t used KDE enough to make much comment)
Not sure how it stacks up overall, but from what I gather it’s essentially built on top of Ubuntu with a few extra bits and pieces, and comes preconfigured with a lot of stuff out of the box which makes setup a lot easier for someone that already has enough to figure out about what’s going on 
And as mentioned above, it’s probably worth trying out a couple of LiveCDs of any cantidate distros you’re thinking of trying out. Good way to get a quick feel for whatever one you’re looking at.
Personally I like the Gnome interface and built-in programs, but I find most apps I prefer using are KDE-based.
Right now I’m just using Kubuntu straight, and it works well enough for me.
KDE (Kubuntu) seems superficially more Windows-like, with a taskbar on the bottom and such. You can use any and all programs from either version. It seems that there is more support online for Ubuntu, as it seems more popular.
It really doesn’t matter. You’ll be able to use all the same software regardless.
That said, Ubuntu is more popular and it has a little bit more support for it in the form of message board threads. (The message boards at the Ubuntu main website are very good.) I’d go with that if I were a complete newbie again.