One of the most desirable motorcycles ever built hits the block today, and you can expect bidding to reach well into six figures before the gavel falls. A 1940 Brough Superior SS100 is among the crown jewels being auctioned during The Quail, A Motorsports Gathering. Yes, that's actually its name, and the super-exclusive annual bash attracts well-heeled petrolheads from around the world. The 1940 Brough Superior SS100 (pictured above) is a special machine indeed, one known in its day as the "Rolls Royce of motorcycles" because it so beautifully combined style and speed. The 998-cc engine was good for 45 horsepower, and every bike that left the factory in Nottingham, England, was personally tested by George Brough to ensure it would do 100 mph. The SS100 was a wickedly fast machine from a company with a rich and occasionally grisly history: T. E. Lawrence — who owned seven Brough Superiors — died while riding an SS100 in an accident that prompted wider use of helmets. This particular motorcycle has a somewhat happier provenance. It was the very last Brough to roll off the production line. It's expected to sell for $350,000 to $400,000. Joining the Brough on the block is a 1954 AJS E95 "Porcupine," a machine built specifically and exclusively for grand prix racing. The bike earned its nickname because of the cooling fins on its cylinder head. Mechanically, it was an improvement over its predecessor, the E90, but the 500cc machine never enjoyed the success of the earlier bike. It was plagued by finicky carbs and had a habit of killing magnetos. Still, it's a historically significant motorcycle and ultra-rare — AJS built just four of them. Auction house Bonhams expects bidding to reach $750,000. Motorcyclists can't resist debating the greatest bikes of all time, so we'll kick start the conversation by listing nine bikes that join the SS100 in our fantasy garage of the world's most desirable motorcycles. Photo: Bonhams

1934 BMW R7 Although this BMW is more than 70 years old, it could pass for a contemporary concept. Master engineer Alfred Böning designed one of the most visually arresting motorcycles ever built, one that was equally advanced mechanically. The R7 featured enclosed bodywork, a pressed-steel frame and telescopic forks — a first for motorcycles. The 800-cc boxer engine, mated to a four-speed transmission, produced 35 horsepower and a top speed of 90 mph. The cylinders and cylinder heads were a single component, with hemispherical combustion chambers. BMW shelved the project as World War II approached. The prototype was sealed in a box, the plans tucked away. It was all but forgotten until 2005, when BMW dusted off the R7 and began a meticulous restoration for its museum. Photo: BMW

Wrenchmonkees' Gorilla Punch This Honda CB750 from Danish builders Wrenchmonkees rocked the custom motorcycle world when it appeared two years ago. It's the antithesis of the chrome-laden, unwieldy chopper, owing more to the Japanese "brat style" of custom bike building. The engine is stock, and the bike has the usual suspension and exhaust upgrades. But that pales in comparison to the styling and detailing; we especially like the solid wheels and oversize tires that somehow look just right. Gorilla Punch ended up as an exhibit at Kunst Industri Museet, the Danish Museum of Art & Design, and was then sold to a biker's cafe in Dubai. It remains a benchmark for contemporary custom motorcycle design. Photo: Wrenchmonkees

Ducati NCR M16 No list of the world’s greatest motorcycles is complete without a Ducati, and our list includes one of the baddest Ducs of all — the NCR M16. NCR is a small Italian outfit that makes Ducati's sharpest apex carvers sharper still. The M16 sports a carbon-fiber frame, and every excess gram has been trimmed from the bike. The swing arm, the fuel tank, the bodywork, the wheels — it's all carbon. The M16 tips the scales at a mere 145 kilos (319 pounds) without fuel. That's less than a MotoGP bike. The souped-up Ducati Desmosedici RR engine has been reworked with aluminum and titanium components and puts out an incredible 200 horsepower at the rear wheel. It's got race-ready electronics like traction control, but you'll still want to go easy on the throttle if your name isn't Valentino Rossi. Price? It's available upon request, and you know how that goes. If you have to ask ... Photo: NCR

Falcon Motorcycles' Black Falcon The Black Falcon is the third in boutique builder Falcon Motorcycles' Concept 10 series. The heart of this one-off custom is a 1952 Vincent Black Shadow engine. The Black Shadow is a legendary machine, one that essentially set the benchmark for performance through the 1950s. This particular engine was discovered in pieces, having led a long hard life in a drag bike. Ian Barry and the crew at Falcon meticulously restored it. The rest of the Black Falcon, except for the carbs and tires, was fabricated from scratch, a project that took five builders a full year to complete. It has already been sold. Photo: Falcon Motorcycles

Honda RC30 There are classic race bikes, and then there's the Honda RC30. Honda built the RC30 from 1987 until 1990, but it remained a dominant force on the track through the early 1990s. The 748-cc V-4 made just 85 horsepower, but the powerband was about a mile wide. The RC30 was a race bike homologated — i.e. sold to the public — for the World Superbike race series. It was, in other words, a racing machine with mirrors and turn signals. Anyone with pockets deep enough could throw a leg over an RC30, and the bike proved popular among privateers, particularly at the Isle of Man TT. In the hands of a talented privateer, the RC30 could beat damn near anything in its day. Honda built around 5,000 of them. If you find a nice one, expect to pay around $25,000 for it. Photo: Honda

Harley-Davidson XR750 Tire-shredding performance isn't a top priority at Harley-Davidson these days. Most of the bikes rolling out of Milwaukee are built for straight roads and long distances — or tooling to the coffee shop. But Harley-Davidson has a long, rich history of building fine bikes, and the XR750 produced from 1970 until 1985 was one of the best dirt track racers ever. The XR won the AMA Grand National Championship in its first year and went on to score more wins than any other bike in AMA history. It also was the weapon of choice for Evel Knievel, which only adds to its coolness. If you’re lucky enough to find one, it could cost you over $25,000 for a well-restored example. Photo: Harley-Davidson archive

Moto Guzzi V-8 The Moto Guzzi V-8 "Otto Cilindri" was a marvel of motorcycle engineering designed specifically for the company's grand prix racing team. The engine was something else, a 499-cc water-cooled V-8 with overhead cams and eight Dell'Orto carburetors. We don't even want to imagine trying to synchronize them all. The engine weighed just 45 kilos (99 pounds), and the entire bike weighed a scant 148 kilos (330 pounds). With 78 horsepower — an unheard of number for a motorcycle in 1955 — on tap, the Otto had a phenomenal power to weight ratio. The bike was once clocked at 275 kph (a smidge over 170 mph) at Spa-Francorchamps. The complex engine proved to be an unreliable maintenance nightmare, and its unprecedented power overwhelmed contemporary tires and suspension. Few riders could be persuaded to touch an Otto by 1957, when Moto Guzzi withdrew from grand prix racing. Photo: Phil Aynsley

Britten V1000 The Britten V1000 is the best motorcycle you've never heard of. But in motorsport-mad New Zealand, John Britten is a household name, if not a legend. Rightly so. The V1000 has been called the greatest motorcycle ever built, and it slayed giants. Britten designed the bike in 1991, and it was a showcase of innovation. It featured a carbon-fiber chassis and wheels, a double-wishbone front suspension and engine data logging. The 999-cc eight-valve V-twin put down more than 160 horsepower, and the bike had a top speed of 303 km/hr (188 mph). The Britten was a formidable racer, beating factory-backed racers in Battle of the Twins races in the early 1990s and setting several land speed records. The Britten Motorcycle Company built just 10 motorcycles before Britten died of cancer in 1995. Photo: Harry Ruffell