I thought it may be fun to discuss our thoughts on what equipments will have the lowest marginal improvement vs. the dollar spent. And at what price point does the margin of improvement sharply drop off in various equipment?
Just to give an example, I believe there is a very low (if any) audio improvement between a $1,000 turntable and a $2,000 turntable (table only, not talking about cartridges). BUT...there is a significant amount of improvement between speakers that cost $1,000 vs. $2,000!
In my experience, the lowest improvement for the dollar spent is in the phono cartridge and speakers. Even the cheapest of cartridges, such as the Audio Technica CN5625AL, make great music when mounted on a quality turntable and arm, such as an LP12/Ittok rig, and cheap, simple speakers (e.g., EPI 100, AR-18, Cambridge Soundworks Model Six, Bose 301, etc.) can be fully satisfying when driven by a quality amplifier (at minimum, a good integrated from Naim, Linn, Rega, Exposure, Roksan, Audio by Van Alstine, etc.).
Of course, everyone's needs are different, not only in overall quality of sound, but in the parameters of playback that are important to them. I don't need loud volume, extreme frequency extension, expansive soundstaging, and am not overly concerned with issues like transparency, air, harmonics, and timbre. What I've found I do need is pace, rhythm, dynamics, and pitch integrity (tunefulness).
Price breakdown:
'table/arm: margin of improvement starts to drop off at about the $3000-4000 range for me because models like the Rega P7, Linn Majik LP12, and WTRP offer a standard of performance significantly above units only slightly less expensive, a standard I could live with long-term.
cartridge: Unless a person has gone whole hog on a "supertable" (maybe an LP12 with Keel, Radikal, Ekos SE), I just don't see a reason to spend more than $150 or so on a cartridge. As Linn used to demonstrate, their Basik cartridge (a conically-equipped AT variant that came free with the Basik arm) mounted on Linn's best arm outperforms a high-priced moving coil mounted to a lesser arm. If you want more performance, it's more cost-effective to spend money upgrading the 'table or arm, which you can reasonably expect to last 20 years or more, than dump money into high-priced cartridges that need to be re-built or replaced every 1000 hours or so and still won't perform as well as a cheap cartridge in a better 'table.
amplifier: Good amplification that I've had a chance to hear starts around $2000. The little Naim Nait 5i sounds good, though it needs an outboard phono stage (such as the Rega Fono MM). I'm using Audio by Van Alstine's lowest-cost solid state preamp and power amp (currently $2100 for both, including a very good built-in phono stage). This is the price level at which I think you get clearly better performance than products just a little cheaper, yet gives up very little to much more expensive gear.
speakers: Just as cartridges need a good platform to extract their true potential, if you drive even modest speakers with quality amplification, you can get fully satisfying sound. The other thing you need with speakers is quality stands (i.e., rigid, with spikes to go through carpeting and spikes or possibly Blu-Tack to interface the speaker cabinets, not bits of rubber) so that the power you feed them goes into driving the room, not rocking the speakers. It's amazing what you can gain in resolution and dynamics by just making sure the speakers are held still. I've always liked simple, 2-way systems such as those I mentioned above. Larger, more complex designs not only cost more money, they seem to get in the way of the music, having poorer timing and sounding rhythmically confused. I'm currently using Bose 301 series V speakers. I've auditioned speakers in my home costing over 6 times the price of the Bose, but they didn't increase my musical satisfaction.