Now that I have convinced you that solid-state drives (SSDs) are the way to go for a computer's main storage, the question is which one you should get.
While SSDs are all very expensive, depending on the features, capacities, and interfaces, their prices vary considerably. If your computer only supports the SATA 2 (3Gbps) standard, which is currently the most popular on any type of computer, an SSD of this standard like the Samsung 470 would be a good investment.
On the other hand, if your computer supports SATA 3 (6Gbps) or you want to get a "futureproof" drive that you can retain and use with future computers, it's better to get one that supports this higher standard.
While most SSDs come in the 2.5-inch design (for laptops), some of them come with a drive-bay converter so they can fit in a desktop easily, such as the OCZ Vertex 3. For an SSD that doesn't come with a converter, you can get the converter separately or even get away with leaving the drive inside the computer's chassis without screwing it tightly to the drive bay. This is because SSDs are much lighter than hard drives, and have no moving parts.
After that, the only question to consider is the capacities. Generally drives of 480GB or larger are just too expensive to make sense as a purchase, even for those who can afford it. You'd be better off getting an SSD of 240GB or smaller, which costs around $500 or less. You only need one to function as the main drive that hosts the operating system of a computer. For extra storage space, you can get an external hard drive (for a laptop) or another internal hard drive (for a desktop).
To save you time spent looking around, here's the list of latest CNET reviews of top SSDs.
Note that while SSDs are much faster than traditional hard drives, they are a different technology and therefore need to be taken care of differently. Check back soon for a post on how you can take the best care of and get the most out of your SSD.