The main problem with LED lighting, especially with picking a favourite or indeed mentioning types that other people might actually be aware of, is permeation of types... basically we're getting the situation where every Tom, Dick and Harry with a big shed and some pillar drills think they can build a streetlight - and the results are a vast array of random company names (most with 'inspirational' sounding names...
I'll make one up on the spot, "Evolution Lighting Ltd - transforming the urban environment") making what are to be quite honest fairly generic lanterns. And the only reason people could, for example, identify the type when passing by on a train would be because their own area has the same types installed and they wanted to find out what the lanterns were. For example, on my way down to Birmingham on Friday my train passed by Swinton in south Yorkshire which is in the Rotherham borough, the main road which passes under the rail line by the train station is lit by the large version of the TerraLED, but the only reason I knew they were TerraLED's is because of the smaller type being installed locally
It is likely only certain lanterns by the big companies will see any form of roll out nationally, and even then only if the price is right as local councils are on even lower budgets. Any new lighting being bought is to a price (even just £5 difference per lantern can change a council's choice).
The other thing is that these smaller companies likely don't have access to the same control gear that the bigger brands use, so may be of poorer quality even if the lanterns look good. As an example, I like the designer of the 'Clipper' lantern by Advanced LED Lighting because they remind me of old-time fluorescents
http://www.advanced-leds.com/products/clipper/However the LED drivers are awful in them and they seem to burn out in just a few months of use (though the ones in Blackpool seem to have been OK) - and the design itself is not watertight.
Some lanterns don't see many installed even in a local area... I like the Thorn Isaro design, and at night they light the road fairly evenly - but likely due to cost there is only one street in York lit by them.
Then a design one person likes may be hated by another or may vary according to size. The Holophane V-MAX looks decent in a 3-tier design for main roads due to being better proportioned, but the single tier side road version looks more like WALL-E than a street light.
Or a design might get changed and made worse. The Holophane Factor Small is an acceptable design, as from the side it looks like a bowl-less Beta 79. But it seems the lantern has been redesigned, and made worse by making the optical area smaller:
So because there's so much variation it's hard to pick out ones that could achieve 'Iconic' status. Simply because of what it stands for, I'd put the Stela Wide forward, even if it does look like a roof slate on a stick - simply because the Stela was the design that propelled LED lighting forward to what we see now, and the curved face of it means that light distribution from it still excels over some more modern offerings. I'd also put the Speedstar forward as it has a pleasing daytime appearance and excellent light distribution at night coupled with Philips control gear for reliability.