Acid vs. LSD?

[robbyam]

I was browsing the store for hallucinogenic doses, and I saw both acid and LSD, but if I'm not mistaken aren't those the same thing? (Lysergic ACID Diethylamide). So what's the difference? Also, which hallucinogens do you think (from personal experience and which you think most people use) are best for:
a) open eyed visuals
b) closed eyed visuals
c) long lasting after the dose
(These can be any, not just acid or LSD).

Thanks.