Recommend a desktop nearfield speaker for me

"Better" is going to be a very relative judgement here.

First, manufacturers provide minimum suggested power requirements based on their statistical measurement analyses of their product under rigidly controlled conditions in order to define a base of repeatable performance.  Accordingly, you should use them as a guide, but only a guide.  Your desk is not a rigidly controlled and repeatable environment.  In the real world, more power is a means to exert tighter control over a dynamic element at any given output.  Thus, one could argue that you should obtain a better image at lower output with a more powerful amp.  Only your ears can make that judgement for you.

Second, understanding of electromechanical dynamics, the electronic devices that control them and the eternal quest for efficiency (read lower cost) has grown substantially since the BBC developed the LS3/5A design.  One could argue that the KEF LS50 is the modern iteration of the first truly successful broadcast monitor design that they themselves produced drivers for way back in the day.  Having recently auditioned modern KEF dual concentric speakers, I would posit that the engineering has progressed to a point where the two approaches have diverged entirely.  They do similar work, but are no longer designed to the same purpose.  Only your ears can decide which approach suits your purpose. 

Finally, the LS3/5A design was most famously produced by Rogers for decades.  Since then, ATC, Falcon, Graham Audio, Harbeth, PMC, Spendor and Stirling have produced the same basic speaker in 8, 11 and 15 ohm variants using Celestion, Falcon, KEF, Rogers and other British drive units.  Why would so many different companies produce so many minor variations on the same theme for so many years?  Because the basic design does precisely what it was intended to do.

Since the deciding factor will be how you like the sound, audition the LS50 and any of the more traditional LS3/5A designs, then buy the pair you like the most.  Then sit down and enjoy the music because at that point, everything else is merely a distraction to the goal:  Happy listening.

I use a pair of Cabasse Rialto speakers as my desktop/computer sound source; they ain't cheap by any means and they're quite heavy, but they sure sound great....

@effischer Very interesting, thanks for the detailed response. When you say the two approaches have diverged entirely, what do you have in mind about the two directions in which the products have diverged? As in, what characterizes those two directions? Is one of those two directions more aligned with extreme near-field listening (e.g., desktop use) than the other?

+4 on the P3ESR. It’s an excellent sounding little speaker and IMO beautiful in Rosewood. It is not exactly balanced, having a bump in the lower midbase, but that bump would work for you as a desktop speaker, supplying a pleasing low end that remains integrated with the overall, lovely sound.

The dual-concentric KEF I auditioned was not the LS50, but did incorporate the same driver and employed a similar non-resonant cabinet design.  To my ears, I felt the design goal was for a mid- to large-field image.  Bear in mind that was one 30 minute audition in a dealer showroom with source material I did not know well.  My belief is that KEF has paired a lower material cost approach with a great deal more engineering skull sweat.  Whether or not my supposition is on the mark, the sound  was not presented in a way that paid homage to the broadcast monitors deployed in cramped quarters of yore.  I'm not at all certain how the speaker would fare in a desktop environment.

The traditional LS3/5A design pairs an extremely well-researched sealed volume and resonant cabinet with similarly proven drivers.  The mid-bass bump @wrm57 mentions has been documented many times and is there for a reason:  The design was intended to be used in a very small space (e.g. the interior of a broadcast van) with the engineer sitting perhaps three feet away with a noisy exterior environment.  Clarity and definition across the transmissible dynamic and frequency ranges were the first priority with image created more by speaker placement than anything else.  That bump allowed the engineer to hear things that could easily have been muffled or obscured by a passing truck or a cheering audience.  That's also why there are entire volumes of commentary about "proper" LS3/5A height, distance from back / sides, toe-in, down / up angle and so on.

All of those things can make a difference to the listening experience with either design approach.  The guidance you're really asking for is which one the AgoN forum participants feel would be better in your environment.  If it was my money, I would definitely go with an LS3/5A variant because what you're doing is exactly what it was designed for from the moment the pencil first hit paper.  It remains good enough to this day that it is a standard against which many other small speakers and certainly most source material, transcription decks and upstream electronics can be compared.

Your budget allows you to consider pretty much all of the best speakers the size class.  As would most others here, I strongly suggest you go do a few auditions and attempt to mimic the distance and sitting height in your office area.  My opinion is my opinion and may not be suitable for you.  In full disclosure, I've owned a pair of the LS3/5A's big brother for decades (BBC LS3/6 / Rogers Studio 1 / Graham Audio LS8/1).  I bought them back in the day when I was in the biz and had Accustat, B&W and DCM to compare them against on the shop floor.  I have never tired of them and would be very hard-pressed to find something that sounds as good for 5 times what I paid in today's dollars.  I turn the system on, stream some stuff to warm everything up then settle in.  Then I start to tap my toes and smile.  That's happy listening!