The PC philosophy is pretty much the anthesis of the Amiga. Driven by Intel it has steadily driven everything onto the central CPU. A standard PC these days has very little dedicated hardware, only the GPU remains.
I dunno - I'm no hardware expert* so please correct me if I'm wrong, but it seems like the average PC these days does at least as much to offload stuff from the main CPU. The Copper might have been revolutionary for its time, but don't forget that it had three instructions - all it could really do was poke values into the custom chip registers at a given point on the screen. You could do amazing effects with the Copper but (I'd imagine - I've never programmed to the metal on an Amiga) you cannot do complex stuff like writing a value to a register conditional on the value of something else, without the CPU getting involved at some point. At any rate, the GPU in my x86 system does much more as a co-processor - the instruction set on a modern GPU, while being highly specialised for graphics, is capable of doing all the sorts of operations a CPU is and applying them to graphics.
Then there's sound: As far as I'm aware, Paula just grabs samples from the chip RAM through DMA and plays them out of the audio channels (taking into consideration the registers for stuff like channel volume) - she's not a processor. The EMU10k1 in my ageing SB Live card is a full-on DSP that can be programmed to run arbitrary effects on the audio stream. From what I understand that'd eat up CPU time on an Amiga (although Commodore were moving in this direction with their plans for a DSP on the A4000). You can even get physics processors now that run little programs to deal with stuff like object interactions in 3D space (the Amiga may have had collision detection between sprites, but a physics engine can then go on and determine what to do with the objects that collided, without having to ask the CPU at all!)
All-in-all, I'd say that the modern PC delegates tasks to other processors that the Amiga didn't. Not that this diminishes the Amiga whatsoever, given it was one of the first architectures to do this to any great extent

* Final warning: I'm really not a hardware guy but I think most of what I've said is kinda accurate:lol: