Deciding for a Laptop which works with ubuntu without a problem (No driver issues)

I am a PhD student in physics.

And I am making simulations on computer. I want to continue my studies at home but my current laptop has a issue with Ubuntu. The graphic card doesn't support GNU/Linux drivers. So I can't visualize my data as I want.

Now I decided to buy a laptop which has a powerful CPU and relatively good graphic card. But I can't buy just a computer because I do not know if it will work fine with Ubuntu. You can tell me to ask the local vendors but In my country computer sellers doesn't have much knowledge about GNU/Linux.

So if somebody can help me to choose a good laptop with good configuration (Money is not an issue I have earned a scholarship to buy a computer to myself :)) I would be most happy.

I do not know if this is the right place to ask such a question but I just need help. I look for a few websites like linuxfordevices.com but that has not the information I want.

I am not a super computer geek so I want to minimize my problems with computer and foucs on my researches.
Thanks in advance everybody,
Thank you...