When shopping for a case for your brand new iPod, you are faced with literally hundreds of different styles, colors, and accessory options.  This guide will overview the most popular kinds of cases.

Aluminum (and other metal) Cases

Metal cases provide the most protection.  As opposed to plastic, cloth, or silicone, an aluminum base boasts the strongest material, designed to offer maximum protection to your iPod.  These metal cases are rarely drop-tested, but between all your options, the metal case gives you the best chances that your iPod will be left unscathed and working perfectly after an accidental drop.  Most aluminum cases are scratch resistant, and the cases will roughly look the same months after purchase (assuming normal wear and tear).  While the outside of the case is metal, the inside of your typical case is lined with neoprene (a synthetic rubber).  This provides a durable, soft inside that absorbs shock from falls and bumps, and also allows you to slide your iPod in and out of the case without scratching the edges of your iPod.  Most cases provide cut-outs to allow you to use a sync & charge cable and headphones without needing to remove the iPod from its case.  However, aluminum cases (like all cases) are often not compatible with cradles.  Most aluminum cases will include a belt clip.

There are two main downsides to aluminum cases.  First of all, they typically add the most bulk.  Especially if you value the size and weight of your iPod (such as the Nano or Shuffle), you may not like the extra size and weight that the case adds.  The other downside is the lack of style and color.  Most metal cases are either black or silver, and they all pretty much look the same.  the only real choice most cases offer is whether you want a cover that is entirely metal, or one with cut-outs for the scroll wheel and/or screen.

Overview:
Pros - Best protection available for everyday use and drops, most durable case
Cons - Typically the bulkiest case, lack of personal style
Search aluminum cases for: iPod Nano, iPod Video, iPod Shuffle, iPod Mini, all other models

Plastic Cases

Plastic cases offer you solid protection while keeping the current look of your iPod.  This case sacrifices some of the protection that the aluminum case offers to keep the great look your iPod already sports.  These plastic cases will offer all the protection you need for regular daily use.  However, if your iPod happens to suffer from a short fall, your iPod will likely survive, but the case may crack or shatter.  Most plastic cases are entirely plastic, with no soft lining for shock absorption.  These cases are often quite cheap, so purchasing two or more at a time with combined shipping may be a wise decision.  Virtually all plastic cases have cut-outs to allow the use of all major functions, including the use of a sync & charge cable.  These cases are not as scratch resistant as metal cases, so over time your case will likely accumulate scratches, decreasing its overall look.

NOTE: Other keywords for plastic cases include "crystal case" and "clear case."

Overview:
Pros - Good protection, keeps the beauty of your iPod
Cons - Case may crack or shatter if dropped
Search plastic cases for: iPod Nano, iPod Video, iPod Shuffle, iPod Mini, all other models

Silicone Cases

Silicone cases offer limited protection but the best functionality.  A silicone case (also commonly known as "Skin" or "Sleeve"), is a thin, stretchable layer of silicone that snugly wraps itself around your iPod.  This offers some shock absorption, but these cases usually have cut-outs for the screen, leaving it exposed to possible scratching.

The silicone case offers the most versatility in regard to other accessories.  Many silicone cases offer easy to use armbands with two slits cut into the back of it, and many include lanyards.  The other nice thing about silicone cases is the variety of colors available.  You can get solid colors like white, black, green, pink, blue, or glow-in-the-dark -- or ones with other artistic designs.  Many auctions will include three or more cases in a listing, giving you the option to change the color and style of your iPod at will (like clothing for your iPod).  Most silicone cases do not offer belt clips.

NOTE: Many people confuse "silicone" and "silicon."  While these cases are truly made of silicone, conducting a search for "silicon case" will likely find you more auctions not found with "silicone case."

Overview:
Pros - Excellent versatility with accessories, excellent variety of colors and styles to make your iPod unique
Cons - Least protection of all types of cases
Search silicone cases for: iPod Nano, iPod Video, iPod Shuffle, iPod Mini, all other models

No Case

Of course every iPod owner has the right to keep their iPod unprotected without the use of a case.  This will preserve the initial size and weight of your iPod, while adding no bulk.  However, with each drop, bump, or scratch, your iPod becomes less and less attractive, while increasing the risk of damage that will permanently render your iPod useless.  The mathematics certainly support the purchasing of a case.  While many people spend upwards of $400 on their iPod, spending roughly $1-$10 for a case to preserve that investment is a wise decision.  We certainly recommend that you purchase one to reduce the risk of a broken iPod, and so you can have peace of mind that your iPod is protected.