selecting a notebook computer for measurements (audio and otherwise)

The following is a general inquiry. I don't expect long responses or a huge
amount of information.

My IBM 765D is so long in the tooth it resembles a naked mole rat. It's
become little more than a portable serial port, for connecting to my
audio-system controller and its remote control, as well as to the serial
tower for the original MindStorms.

Next year, when I finally retire my outstanding debts, I'll have the money
to buy another machine. I don't absolutely need one, but a hefty
"desktop-replacement" model with a huge screen would be nice. (It doesn't
have to be compact, because it's unlikely I'll be carrying it around all the
time.)

I'm wondering... Is there any really sophisticated audio test software out
there? I know, I know... What do I mean by "sophisticated"?

Many years ago I worked for a company called Barclay Analytical. They made
an analyzer -- the BADAP -- which did such things as displaying the
real-time decay spectrum of a room's reverb characteristics, in 31
third-octave bands. A fancy FFT with a waterfall display would be nice, too.

Thanks in advance.