Hmm.... great question. Probably depends on your listening habits.
However, my thoughts:
For UTE and AM Listening, it's got to be the R-390 Receiver. The audio is warm, and the selectivity is outstanding. It is a monster, built like a tank, and you can get a good condition one for around 500 bucks.
For late model receivers, the R9000 is a favorite, along with the Harris RF-590...
Well the guy did ask "BEST". Best would be what the government buys. You can bet that the CIA, NSA...dudes and dudettes like them are using the "best" that money can by.
A tube rig example of that bygone era would be the Collins-made? R390 & 390A
Some of the big boxes of our solid-state times are the afforementioned Harris', the Racals, the Watkins-Johnson units. Several model lines in each. No doubt there are many others. These big boxes show up on the used market and even used and on eBoink go can go for over $2,000
Maybe you really want to know about consumer variety high end table top rigs. The Icoms and Kenwoods with the large model numbers like 5000, 7000, 9000 are big time nice rigs and you can still expect to pay the big bucks for them on the used market. Expect to pay about $800-up for these.
These rigs about all do the DC to Daylight thing, will be triple if not quadriple conversion on the receiver scheme, and have every other feature and function you can possible dream of.
Anything less than these models and you're moving way under the "best" tag, unless you want to chat about portable units.
AOR AR5000 (~$2600) and AR-One (~$4500), Ten-Tec RX-340 (~$4300), etc...
"Best" is really kind of subjective, and once you get to the level of the receivers mentioned in this thread it essentially becomes a contest of feature requirements and personal preference rather than on-paper performance.
to see the government surplus from CIA and other monitoring stations, check out the commerical grade equipment at www.torontosurplus.com and you will see even surplus they still costs a pretty penny. The R340 is great, and also go to the TenTec site and check out the new R400. One thing that is really needed is DSP and many of the old classics do not have this capacity.
My favorite is my TenTec Pegasus as I use it both for ham and Navy MARS along with HF monitoring. I use a third party software with it that permits almost unlimited number of saved frequencies with alpha/neumeric titles.
I vote for the ICOM R-71A, but the Kenwood R-5000 is another strong favorite. However, my heart belongs to my Hallicrafters WR-600 or the Zenith Transoceanic that was my grandfather's shortwave receiver.
I would completely agree. My first receiver was an old (well worn and used) Hallicrafter S38B! Had a tiny, tinny speaker but I remember it fondly and well. The Hallicrafter SX100 also had a good sound, especially with a decent external speaker. However, I digress and have now dated myself as older than Noah's grandpa.
This question is way too broad, and pretty much subject to individual interpretation; the best desktop radio for what application? The best portable for what - traveling, SWBC, ect??
I think for portables, you have to consider the ICF2010 as being the standard. Even tho it's been out of production for years, many reviewers will compare their radio - whatever they are reviewing - to a 2010 if they have been following the market for any length of time. True, it has a habit of blowing FETs in the front end (at least the earlier versions did), but it had things absolutely no portable had in its day - sync detection, generous memory and was very flexible insofar as what you could do with it. SWBC and even some utility stuff was very possible with it. I personally knew many VoA correspondents who, at the time, swore by the 2010 no matter where they traveled.
Desktop - hmm, that's a tougher question. I'd have to say the Drake R8B and AOR7030 had to be considered if not tops, at the very least in the top 2 or 3. Many folks also swore by (some I know swore at...) the Japan Radio Corporation NRD535 or NRD525.
JRC actually built its radios a lot tougher than what you would find in the commercial market. That was because they weren't - they were (and I think still are) a company that built their radios for the maritime market. It's true that some (including myself) thought the audio was too wooly for their taste, but the selectivity and sensitivity would give any commercial radio a run for its money.
I heard a story about one of the older JRC radios - a NRD515 in fact - from Larry Magne (yes, of Passport to World Band Radio fame). Evidently at one time they had a remote monitoring station set up in the jungles of Paraguay; during a fierce T-Storm, the antenna took a direct hit. The radio's cabinet was badly singed, but the radio still worked after a few boards were replaced. That would speak volumes about the grounding system used at that station, but also just how well that radio was constructed. Swap a couple of boards and get back on the air quickly - try THAT with any of the HF radios today.
By the way, I've been a NASWA member for over 20 years, and ran a SWL/Tech net in the Baltimore Md. area for almost a decade; I've seen reviews on these radios, and more, over those years. I'm willing to bet that those I've mentioned are in the top 10 in the world, both then and now.
What are your criteria?
Is it most sensitive, best sounding, most resistance to interference, most reliable?
I have a bunch of receivers, from an Icom 8500, 9000, 756Pro and R75, a Collins R-390A, Watkins Johnson 8618A, Racal RA6217A, Drake R8A, Yaesu FR-101, and the computer controlled SDR-14, RX320, and PCR1000.
They are all very nice receivers.
From my stable,
Most sensitive = Collins R-390A
Best sounding = Icom 9000 or 756Pro (the 756Pro has very nice noise reduction, so it is better in noisy conditions)
Coolest = SCR-14
Best all around = Icom 9000
I like to Icom 9000 because it covers the whole spectrum, it is very sensitive (especially on HF), it sounds great, and the scope is super cool and very useful.
The next best would be really tough. I love the Collins R-390A, and I love using it, but you just can't physically fly up and down the bands with it.
I would also give a special nod to the SDR-14. It is so cool and really changes the whole HF listening process. I can actually see the entire HF band it one time or just pieces of it. It makes monitoring an entire band very easy and it helps me identify and listen to more signals than I even have been able to. Check one out!