Simply mentioning these races conjures up ominous images of dark beasts powering through cobbles, mud, and shit. Each rider trying to hold the wheel of the next, grim faced with eyes focused ahead. Merckx, De Vlaeminck, Godefroot, Moser, Maertens, Kuiper, Raas. The riders today still race over the same cobbles as the names of a bygone era.
A rider that wins one of the greater races, like Tour of Flanders, Paris-Roubaix, or Milan-SanRemo is a man that can forever rest on his laurels. They are often referred to as "inhuman" while in pursuit of victory. They drive huge gears that would turn any chump that says they average 25 mph into a snivelling bush of dangling clinkers.
Some of the newer guys on the scene are Tom Boonen, Magnus Backstedt, Juan Antonio Flecha, Filippo Pozatto, Nico Mattan, and Fabian Cancellara. Dudes you undoubtedly would never mention your training rides and max wattage to.
If you don't know about the spring classics. You'd do well to know more about them. Lance would be disappointed if you didn't
"A Paris-Roubaix without rain is not a true Paris-Roubaix. Throw in a little snow as well, it's not serious." - Seán Kelly
"When you attack in Paris-Roubaix, you don't have to think. It doesn't take five minutes to work it all out. You just do what feels right at the moment." - Johan Museeuw
"Paris-Roubaix est une connerie" translating "Paris-Roubaix is bullshit"-