MGS, Lord of Shadows 1 and 2, Dark Souls, Dragon's Dogma, ZoE: The Second Runner, Dragon Age 2, Persona 3 and 4, Final Fantasy VI, VIII IX and X are the most memorable to me, because I enjoyed the music in them, and would stop to listen to them too. 

ones that really stick with me have been ending and boss OSTs

[youtube]TLxv_g_zQkY[/youtube]

[youtube]2J7tpDGq4GI[/youtube]

[youtube]btys5pB4LrE[/youtube]