If you're just looking to experiment to see what software's out there, if you can live without 3D acceleration, I'd probably recommend just setting up a VM on the desktop and running Linux in that.

If you're wanting to use it on a semi-serious basis, kind of depends on what price range you're wanting.

In the past, I've tended to use ThinkPads, which are not the cheapest brand out there, and are generally business-oriented rather than gaming -oriented. However, I prefer physical buttons, and they do have a built-in Synaptics trackpad with three physical buttons; Linux makes more use of the third button than does Windows, so this is convenient. They also had a long-running reputation for solid build quality (i.e. not having problems with hinges breaking or similar issues).

In general, I've been less-happy with newer ThinkPads, and last I looked, many no longer have physical buttons.

That may not matter to you if you don't care about physical buttons or use a mouse/external trackpad/trackball or similar all the time with laptops.

ThinkPads also don't typically have terribly bright screens, which again, may or may not matter to you.