Turntable versus tonearm versus cartridge: which is MOST important?

''The terror of grammar''? Each comparison imply relational 
context:  ''x is better, larger, etc, than y'', But the grammar
force you to put this relation in ''x is P'' grammar form . That
is  ascribing some property to the object x. We don't say 
''Peter is bigger than than Gorge'' but ''Peter is big'' and
'' Gorge is small''. This way  we get ''big Greek Populos''
loosing his ''property big'' in, say , Holland in which he become
'' small''  because the  Dutch are the longest people in the world.
Such ''riddles '' of course also apply to analogue comparisons
between components. 

Luthuania you say. Where Lex Luthor lives? ;)

Not exactly, Lithuania is not far from Russia 

I have a 12" Cocobolo with Firewire and a 10.5" Ebony with Firewire. My 12" is paired up with my heavily modded TD124 and my 10.5 is on my modded 301. You can see pics in my profile

@fsonicsmith yeah, I like the cocobolo plinth veneer too. That 301 is lovely. 

Lex Luther lives in Gotham. Everyone knows that. Somewhere in the sewer system he has a subterranean mansion.

There's a chap called Mike Lavigne who has an absolute top flight system and is very approachable. I asked him the question and he said that after a certain stage in a turntable it's the improvements in the arm that are the most significant. Cartridges IMHO are often very subjective - liken it to a lens filter that may highlight some aspects better than others. When speaking to quite a few cartridge dealers and repairers of note the impression I get is that above £3000 is about getting the story of some fisherman that makes swords after reading to his grandchildren who only makes cartridges when meditating... I haven't heard enough to say one way or the other.
@chakster as a joke question I bought a JVC QL 10 with UA arm in mint condition for £400 - is a £10,000 cartridge wasted on it?