Surely if "last and best" is your criterion, one can hardly discount the Atari Falcon. (And the earliest models in the Acorn Archimedes line were definitely "all-in-ones" integrating a keyboard although they might have lacked in-built TV out.)
At the time it was launched, 1992, the ARM2 processor inside it was considerably more powerful than workstations that could be bought for ten times the price. It was insanely powerful, but hamstrung by not having any form of graphics acceleration. (The CPU was so fast it was just assumed you'd do everything in the CPU.)
It's a shame, really. RISC OS running on ARM deserved to be the British standard of computing, but Acorn's failure in the US market meant they could not compete with the sheer PR power of the large American competition.
Photos and details: http://chrisacorns.computinghistory.org.uk/Computers/A3010.h...
Maybe it was the OS that caused it, but working on acron was painfully slow.
(Developed a CAD software for it, moved to PC very quickly)
Was just an Atari. Braindead architecture throughout.
It is remarkable how the 68030 still had to wait for its turn to access RAM. Like the ST, Falcon had no concept of FAST RAM.
Falcon had a cool DSP chip in it, but that's about it.