The main advantages of using SSD is speed closely followed by reliability. For the common Joe, they'll never really need a SSD in their systems.
Hold it right there.
Reliability? There isn't any solid evidence that shows this to be true. The MLC flash chips has a lifetime that is much lower than SLC chips and the current HDD technology. As of right now, it is not a major benefit over the HDD. However, if you are talking about the g-shock, yes SSD is excellent in that field but 99% do not even touch the g-shock limit of the HDD nowadays. Even if it does, HDD are mature enough to handle those g-shock with sudden motion detection and head packing technology. This could change suddenly with the possibility of a company coming up with a new innovative technique to produce the SLC memory cells much more cheaper. This probably won’t kill MLC however it is possible that SLC will become the main OS/App technology with the MLC used as storage technology since the read speed and longevity of read-only data is much more tolerable. Hell it is possible there’ll be a write once, forever read-only MLC memory chips that could hold far more than 2 bits per transistor and could last more than 50 years. It could become the new “tape” archive drives. I doubt it, but than again, we never know.
Same goes for speed, the read speed may be much faster than the typical HDD (only in the high end market which is currently very expensive), it isn’t true for write speed in MLC SSDs at the moment. One of the biggest advantage of SSD over HDD is of course is the seek time, but much of the SSD market is fitted with jMicron controllers that eliminates the benefit since the stuttering is enough to wipe out the advantage of the seek time. We have to wait several more months for this stuttering issue to go away in hardware devices and several years to a decade for the OS to be optimized for SSD. Even current drives can be made much faster with an SSD optimized OS without any major changes to the hardware.
While it is true that SSD has been around for more than a decade in other area of the industry, it still needs maturity to be a benefit for everybody including the common computer users. When that time comes, the common Joe is going to want a SSD because the HDD right now and in the future will still remain the biggest bottleneck in their system and SSD is the only technology in the market that can eliminate that.
Capacity is not going to be an issue, it'll pass the size of HDD sooner rather than later. Without any major new technology, I do think that the companies are going to start hitting the limit of what the HDD can do.
Price will go down, much faster than we think. It is probably the most exciting technology yet to come. I am very sure we haven’t seen the best of what SSD can do, but I have seen such industry “shakers” before that failed badly, so it is possible SSD could fail horribly a year from now and disappear off the face of the earth as another failed technology.