Since people were talking about crack vs. coke before and looking for personal experiences... well, I've done both,
The highs are similar but vary in intensity. In a word, cocaine is "gentler". You come up slower and come down slower. They both have this quality to them that leaves you wanting more, regardless of if it's a bad idea, but it's worse with crack. People who are really "coked up" on either drug get really annoying, but if you're high too you don't care.
I guess the main difference is that cocaine is something you can use while you are doing something else - at a party, at a festival, etc. Doing crack *is* the activity, since it's so short-lived and everyone always wants more. It also "feels" dirty, like it makes your mouth feel weird and the smoke has a very bizarre taste to it, whereas the numbing effect that cocaine has on your nose makes the act of insufflating it feel sort of nice.
Anyhow, I recommend trying everything once just to know how it is. I don't recommend paying for either though, shit's expensive, just have high people offer it to you. ;-)