I'm not exactly proud of it, but I've had a few experiences with xtc, lsd, and morphene (in a hospital when I had bad food poisoning).. I don't think anything could ever beat the shear nervous feeling from lsd - I remember feeling scared that my heart was going to pop... must have been beating 10 times faster than normal for hours. I've had exhileration but also terrible feelings from it.
It's one thing you shouldn't try...
Here's a good reason why you shouldin't try lsd:
I remember feeling like a different person (kind of sick from a previous stomach ache) and I felt terrible and the feeling would not go away. I spent about 2 hours writing over 50 different post-it notes addressed to my real self begging him never to trip again. When the effects finally wore off, I looked at the post-it notes and they all weren't in my handwriting. The writing looked like that from those old pens that had rotating weights in them - I was shaking that much.
Trust me.. that tiny lil' pice of paper or little dot is a lot more powerful than you'd ever think.