If the issue is reliability then make sure you have a second storage space. Intel is known to be reliable, and that's why I bought the same one you are looking at. I installed my OS, games, and programs without any problems. After I put my OS on the SSD I then created a backup/disk image and saved it to my HDD. So, if my SSD should have any issue I can easily access my backup and fix it.
People will suggest using a SSD for OS and programs. If you want it to last a long time make sure you are not writing to it too much. Like me, I save all my videos, pictures, documents to a separate HDD.
If you buy the 120GB SSD then you should buy a HDD. It's easy to get a good 500GB HDD for $70. Anything lower than 500GB isn't worth it, cuz you can go from a 320GB to 500GB for an extra $5-10.