Honest question about cartridge vs. turntable performance.

IMO you have to divide operational criteria into two categories one for things that are absolutely necessary for proper performance and the second is for sound preference.

#1, speed stability, vibration control, and motor insulation/location (so it doesn't induce hum from the cartridge - not absolutely critical but it can certainly limit your cartridge selection.  Get the best TT you can afford. A good one should last a lifetime with minimal fuss.

Tone arm selection is equally important and cartridge matching even more so but easier to obtain. 

#2, Cartridge selection, phono preamp selection, phono cable selection all affect mostly the sound. BUT their set up is critical so keep your system as simple as possible. One thing that, for me anyway, is critical, is the incorporation of capacitance selection in the pre-amp otherwise you have effectively limited cartridge selection to MM types.

So I agree with big_greg. To keep the cost moderate, and selection simple, I would start out with a high quality integrated TT/Arm in the first place where experts have already taken care of the matching issues, and focus on the cartridge/preamp, cables etc, which are easily changed as your tastes change over the years.

FWIW setting up a good vinyl system ain't rocket science but it ain't a walk in the park either. Do a LOT of research first. 

The turntable is the thing.  Fine turntable and modest cartridge easily outperform the reverse.

A turntable can make a HUGE difference. A tone arm can make a HUGE difference

about 5 years ago I heard a pricey VPI table fitted with a $300 cartridge. That set up was spectacular. Another time I heard a table with a cartridge that was way more expensive that the table. Disappointing- I knew that cartridge was capable of better 

Just get a Rega where everything is chosen for you to optimize performance. They take all the guess work out and eliminate making costly mistakes by limiting the constant mix and match, and allowing you to focus on the rest of your system.

Curious to still see this question 40 years later.
1) the most critical quality to a turntable is its ability to turn a record without imparting or passing through vibration to the record and tonearm.A poorer turntable will collapse dynamics and raise the perceived noise level of a record surface because of vibration transmitted and superimposed on the record groove signal. Another name for this attribute is resolution
2)  a tonearm must track rigidly and accurately while encountering variations in the X and Y axis's due to record imperfections in hole centering and record height. Bearing friction should allow slow movement across the record but damp oscillation at higher speeds... if you see the head of your tonearm quivering  during routine record playback thats a problem
3) cartridges are analogous to speakers, the patent determines their "house" sound, the stylus quality determines the limit of  resolution in
that family

Its is far better to focus your investment on the turntable,get a reasonably competent tonearm and use something like aninexpensive Grado  cartridge.