Go for a Samsung 840 Evo if you can spend the extra money, the write speeds are much improved over the regular 840. Otherwise from this list I'd personally pick the Sandisk. The write speeds on the regular 840 are slow. Maybe even look at picking up a Crucial M4 if you can find one cheap, Crucial updates their software more frequently than anyone else.
Sorry for late answer, was having trouble logging in. Well, the 840 Pro is out of the budget, 120 gb Evo not available and no crucial SSD available as well. I need the SSD to work for atleast 5 years. So, please suggest me a good one. Still leaning towards the Samsung Series 840 120 GB.