SSD drives are not as unreliable as people seem to think, It would take a *minimum* of 5 years of *continuous* writing and thats for the cheaper SSD's like you would find in a netbook rather than the $300 Intel top of the line ones, not to mention ones being used in a RAID would have a longer life.
Besides even if some blocks go bad you can map around them, the SSD itself might even do it.
Besides, you are unlikely to be using the same drive in 5 years time and magnetic drives have a much higher chance of failure, also when magnetic drives die often the entire drive dies at once, a few blocks failing is a much better solution.
In addition to that, the following is from the info on the SandDisc 3G drives: "The G3 SSDs provide a Long-term Data Endurance (LDE) of 160 terabytes written (TBW) for the 240GB version, sufficient for over 100 years of typical user usage.(2,3)", 4GB of writing a day is typical.