This week marks the birthday of one of British music's most endearing guitar heroes, Brian May, who has been a member of the rock band Queen for nearly 40 years.
In 2005, a Planet Rock radio station poll voted May the 7th greatest guitarist of all time. And, while fans continue to enjoy May's work, a few might just be wondering about the collectible value of his guitars...
After all, when it comes to music memorabilia, few things rival guitars in terms of collectible value. And the good news is, there are a wealth of investment opportunities for you on the market.
Signed and unsigned guitars from some of today's legends of music can be purchased for under £10,000 - offering great entry-level investments for some of the most unique guitars out there.
At a Pennsylvania, US, auction earlier this year, an American flag-designed electric guitar autographed by veteran US rocker Bruce Springsteen sold for £2,300 ($3,450).
More visually unique still was the iconic "cloud guitar" owned by Prince, which sold for £7,950 ($11,875) as part of an auction in New York which was held in November 2009.
These artists continue to tour today, but the values of their unique guitars could rise even further once they retire from performing.
Elsewhere, if you're looking to make a bigger investment in signed guitars, there are a number available from the classic rock groups of the 1970s.
Tom Petty and The Heartbreakers enjoyed global biggest success in the late 70s, thanks to hit albums like Damn the Torpedoes.
A guitar belonging to Petty from that period sold for £13,700 ($20,000) at a New York auction in November.
Similarly, T-Rex memorabilia also continues to prove popular, following the death of the group's front man, Marc Bolan. A guitar belonging to Bolan sold at the same New York auction for £19,000 ($28,000).
Another recommended investment in the world of collectible guitars is that of Pete Townsend from The Who. A guitar belonging to Townsend sold for £32,180 ($49,250) in New York in 2009.
Meanwhile, and perhaps unsurprisingly, the American market for collectible guitars is dominated by old stars of Country and Western.
In December 2009, Christie's hosted a Country Music sale with highlights including the sale of Johnny Cash's "fiddle guitar" for £25,000 ($37,500). Even more significant was Hank William's Martin & Co 1947 guitar, which sold for £87,500 ($134,500) over its estimate of £66,000 ($100,000).
But the current World Record price for a Country and Western star's guitar belongs to Roy Rogers, whose Martin guitar was sold for £300,000 ($460,000) in April 2009 at Christies.
From a collector's perspective, the provenance of the guitar also plays a key role in determining its value.
In the world of blues, Bo Diddley's last-ever stage used guitar and case fetched £40,000 ($60,000) at auction in November 2009. Similarly, Elvis Presley's guitar, used in his final Las Vegas performance, sold for £69,200 ($106,200) in a California auction, also last year, in October.
And, at the top of the market, you'll find that value can often be based on a matter of life or death...
In May 2007, San Francisco witnessed the sale of a 1975 cream Travis Bean guitar belonging to Jerry Garcia of cult band The Grateful Dead.
The band had been inactive following the death of Garcia, the group's key member, in 1995. Little wonder then, that the guitar reached £208,000 ($312,000) at the auction.
Much like Jerry Garcia, the value of The Beatles and Jimi Hendrix collectible guitars has soared.
Hendrix was known primarily for his mastery of the guitar, which has helped to make these collectibles some of the most sought after on the market to his fans and collectors alike.
That he died at the peak of his career also helped to heighten demand...
A Fender Stratocaster, famously burned at the end of Hendrix's show in North London in 1967, was purchased by a collector for £280,000 ($320,000) at Christies in 2006.
The current world record price for a Jimi Hendrix guitar was set at £310,000 ($480,000) in 2007, for the 1966 red Fender Mustang used to record his legendary studio albums.
The most sought-after signed guitars related to The Beatles are those used by individuals within the group that have passed away. In September 2003, Harrison's guitar used to write the Beatle's song Let It Be sold for £270,500 ($414,000) in New York.
Yet, the most valuable guitar related to The Beatles, remains a Gibson SG guitar. This was used by Harrison and John Lennon on The Beatles' Revolver and White Album LPs. This guitar sold for £370,000 ($567,500) at Christies in 2009. Guitars belonging to Paul McCartney could eventually see similar prices.
However, the most valuable collectible guitars in the world do not come from a band or any one deceased. They come from a man called Eric.
Eric Clapton is viewed as one of the greatest living guitarists of all time, having been inducted into the Rock n' Roll hall of fame, a record three times.
He currently holds two world records in the world of collectible guitars. Both of which, were set in June 2004, at Christie's in New York.
The first was the world record price for an acoustic guitar. Clapton's 1939 Martin & Co guitar set this, selling for £517,200 ($791,500.)
The guitar had featured on Clapton's famous MTV Unplugged set which many critics point to as a pivotal moment in his career.
The instrument had been given an auction estimate of £55,000 ($80,000).
Similarly, Clapton's Blackie 1956-57 composite Fender Stratocaster, the only guitar he used from late 1970 to 1985, set a World Record price for any guitar ever sold, coming in at £527,198 ($959,500).
With many of these artists still performing in some capacity, the value of these guitars could continue to grow over the next twenty years, making them the perfect investment for fans and collectors alike.
And what of Brian May? Well, a charity auction in London in 2005 saw the sale of one his famous guitars for £3,100. Considering the impact of Queen's smash hit We Will Rock You musical and the potential retirement of Queen as a group, collectible guitars like this could soon prove a "Killer Queen" purchase...
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