In the world of superheroes, Superman may be have the most other-worldly power, but it's Spider-Man who twinges the heart-strings. Perhaps it's his familiarity -- weren't you, too, that nerd in high school? -- or perhaps it's his tragedy, what with his unknowing part in his uncle's death. Either way, two of the most expensive comic books ever sold at auction are issues of Amazing Fantasy 15, the series in which Spider-Man was first introduced in 1962.

One of the rarest comic books still in existence in near-perfect condition is an issue of "Amazing Spider-Man #1," rare not only because of its singularity but also because of its quality. The comic book sold for only 12 cents per copy when it was published in March 1963, and is now worth over $40,000 -- not an exceedingly high price for comic books (the most valuable, first appearance of Superman in "Action Comics 1," is said to be worth $350,000) -- but extremely rare in such pristine condition.

In 2002, a comic book shop in Manhattan was broken into, and a particularly rare copy of "Amazing Spider-Man #1" was stolen, by a "gentlemanly" robber holding a duffel bag containing a rifle and handcuffs. He tied up the store owner while he picked the desired issues -- certainly a scene right out of the pages of his contraband. If only Spider-Man was real ...

When it comes to travel the question of rare is open to interpretation and likely depends on what you dream of doing with your vacation time. For some of us, merely taking time off for real vacation is rare enough. Recent studies have shown that as a workforce we are opting to use our allotted vacation time more and more for long weekends than for the traditional one or two-week immersion escape.

Rare travel used to be easily defined by the exotic. That no longer seems to be the case. Thirty years ago, an African safari would have been considered a rare getaway. These days, people go on safaris for their honeymoon or bring the kids during winter break. Travels to remote islands such as Tahiti or the Seychelles are equally common with luxury resorts setting up shop in just about every corner of the globe. You can even tackle the whole world at once, private jet trips that take you around the world are becoming more popular and likely the recent film the Bucket List will inspire more people to see the wonders of the world. The LA Times found that doing your own Bucket List trip will cost you over $105,000.

Another category in the rare experience category is being able to experience a side of a place that few seldom experience. Often this involves a great deal of money. Concierge recently did a great piece on the world's most extravagant vacations. Many of them offer the type of experience that only money can buy. Take for example the $300,000 week in Paris offered by travel expert Andrew Harper. For your money you get a suite at the Ritz, private tours, a chauffeur, 24-hour-a-day concierge service and dinner reservations at hot spots such as Alain Ducasse and Voltaire. The trip also includes a private tour of the Louvre, a couture fitting at Chanel and a meeting a French custom perfume designer. Other trips on their list include heli-skiing and, of course, a round-the world excursion.

What is the rarest trip? There's no real consensus on this but I would say that the trek to summit Mount Everest still remains among the rarest trips in the world. But even this has become something that is accessible to more people. In two months and for around $60,000 you can join a group and make the attempt of a lifetime.

The obsession with rare antiques is one shared all around the world. One of the things that makes rare antiques so fascinating is that they often don't look that much different than other less precious versions of the same object. It often takes a practiced eye to determine the value. That's one of the reasons that Antiques Roadshow is so compelling to watch, it can be very challenging to guess what value the experts will assign to people's treasures.

One of the most interesting categories is often vases. Small, fragile and exquisitely valuable, vases, especially from ancient Chinese dynasties can fetch millions. In April of 2006, a 20-inch high blue and white Yuan Dynasty vase fetched over $2 million. That sounds rare but at the end of May 2006, casino owner Steve Wynn paid even more for a rare vase. The small copper red and white porcelain vase, is a 14th century Ming vase decorated in scrolling flowers. It is from the exceptionally rare Hongwu period and went for 78,520,000 Hong Kong dollars ($10.9 million) making it the world's most expensive vase. While many thought that Wynn, one of the world's top collectors, would squirrel the little treasure off to his collection he gave it to a Macau museum. An avid collector willing to part with a treasure immediately might be the rarest treasure of all.

There are countless rare books in the world, but by most expert's standards the rarest of them all is the Gutenberg Bible. It was the first book ever printed back in 1456, and although several hundred copies were originally printed finding a complete first edition would net you $25-$35 million. In today's market single pages alone go for $25,000 each, and several years ago just 1 volume (it's a 2 volume set) sold for $5.5 million.

Besides the Gutenberg Bible other rare books include the first edition of Shakespeare's collected works from 1623 (worth $6 million), a collection of Leonardo da Vinci's manuscripts (potentially worth as much as $100 million), and of course any first edition copy of the Declaration of Independence (worth $8 million). Edgar Allen Poe's work also makes in onto the "rarest books" list with his first published poem ("Tamerlane") being rare and difficult to find due to a byline of simply "By A Bostonian." It's worth as much as $200,000 to the right buyer.