Most hard drives in computers today all have a significant chance of failing. This means that they may stop working due to the fact that conventional hard drives have mechanical moving parts.

Today's "modern" Solid State Drives have greater life expectancy. It uses the same type of memory as a "thumb drive" flash memory. The likelihood of an SSD failing is very minimum compared to the HHD traditional hard drive.

Follow up:

Now that floppy drives are essensially obsolete because of the fact that the data can easily get corrupted it seems as if the traditional hard drive, with moving parts, is about to become obsolete.

Why should I get an Solid State Drive?

There are many reasons why that are listed in the video provided above. Lets go through some of the obvious reasons:

Life Expectancy

1 - The Solid State Drives are less likely to fail because there are no moving parts. Thus the name "solid state" drives.

Speed

2 - The read and load times of the SSD are far faster. This means that you can start your computer up in about half the time, as many studies and demonstrations seem to point out.

Weight

3 - If you have a laptop and weight is important to consider, you can be assured that the Solid State Drive will weight less.

Durability

4 - If you are sometimes careless with technology or have situations were the computer may be damaged or dropped there should be less of a worry about the hard drive because there are no moving parts that could be disrupted.

Reasons for not getting an SSD

One of the big reasons is that the price of the SSD is still up. A decent 64gb SSD can be $200 or more in price. Which may not be enough space for your files.

Another reason is that many people have a lot of data on their current hard drive. A solution that some people would do is backup all your data. (pictures, application files, music...) Then install the Solid State Drive, after which you can install your operating system such as Windows Vista.

If you still have a mechanical hard drive and have the money to get a decent Solid State Drive then do it. Data can be very important and flash memory can keep it solid.