If I asked you to guess an investment that can give you 500% appreciation of six months, what would it be?

I'll bet that guitars wouldn't be your first response.

In the forty years since Jimi Hendrix played his white Fender Stratocaster before a 500,000 people at Woodstock, guitars are now firmly established as collectible items.

Such legendary events have led thousands of enthusiasts to seek out vintage Fender Stratocasters from the 1970s.

A late '60s Strat', then worth a couple of hundred dollars, can today sell for as much as $30,000.

Other items, like a '60s Gibson Les Paul Jr., can appreciate by an incredible 500% after six months of ownership.

And the best news is, with the guitar market down alongside stock prices, there are plenty of opportunities for new investors.

"Now, the baby boomers that bought the guitars are selling them back," Harvey Moltz of Rainbow Guitars, an Arizona-based vintage and modern instrument dealership, told Forbes.

Guitar prices are dropping by as much as 40% - so dealers like Moltz are stoking up their storage rooms with vintage guitars for the first time in 30 years.

There is one particular factor that can guarantee a guitar's appreciation...

Aside from being in mint condition (with original parts, electronics and paint), the guitars must be tied to an artist or event that resonates in the modern popular conscience.

For instance, 1980s ESP guitars were played by, and are associated with, Metallica.

While such guitars hold value now - particularly with today's wealthy who loved metal in their youth - the value of shred-friendly guitars is likely to fade as the collectors themselves age.

But Woodstock and other classic-rock-associated guitars are likely to increase in value yet again - partly due to music releases and merchandising from labels like Warner Bros to coincide with Woodstock's 40th anniversary.

But, even if prices are more affordable - with a '56 Gibson P-90 Les Paul Gold Top dropping from $80,000 in 2007 to as little as $35,000 - you should still be cautious with your cash.

The year of a guitar's manufacturing date can affect the value dramatically.

For instance, electric guitar production increased dramatically after the Beatles' 1965 North American tour. Guitars from this era are less rare, and therefore less valuable.

A scarce guitar is the black mid-'60s Gibson ES-345 played by Jefferson Airplane's Jorma Kaukonen at Woodstock. The model is a much rarer find due to its colour.

Many guitars can increase in value over time, but few instruments will exhibit the long-term value or prestige of Woodstock instruments, despite their current (relatively) low prices.

Here are some guitars to look out for....

Carlos Santana

Guitar: Pre-1965 Gibson SG Special with P-90 Pickups

What You Should Pay: $5,000-6,000

These guitars were the favoured choice of Santana and Pete Townshend even after Gibson phased it out in the '60s.

Stephen Stills

Guitar: Late-'50s Gretsch White Falcon

What You Should Pay: $30,000

This guitar has not been hit hard by the recession, and has the potential for future growth in value due to its connection to several star performers.

But avoid post-1967 models. Baldwin manufacturing bought the company from Fred Gretsch, and made poorer-quality guitars.

Jimi Hendrix

Guitar: 1968 Olympic White Fender Stratocaster w/all-maple neck and cap

What You Should Pay: $25,000-30,000

Don't buy just any '60s Strat, as not all have Hendrix's rare, all-maple neck, fingerboard and Olympic White paint. Non-Jimi models depreciate more due to generalisation of value.

To buy the Jimi Strat, you'll have to pay big, but your investment will be safe. The link between the instrument and Jimi is enough to keep this guitar - made after 1965 - appreciating in value.  ____________________________________________________________

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