I've tried all these drugs at one point or another during college, and let me tell you from first hand experience that coffee is the hands down winner. It's ch

I've tried all these drugs at one point or another during college, and let me tell you from first hand experience that coffee is the hands down winner. It's cheap, readily available, 100% legal, not regulated, delicious, and gives you motivation in addition to performance. Furthermore, you can do it with other people in a social setting and you can do it fairly regularly (every morning and lunch) without completely wrecking your biological sleep cycles. It warms you up on cold days, can cool you down on hot days, will refresh you on both, and there's a ton of cool paraphernalia associated with it that doesn't put you into creepy junkie territory. The most important of all: you have perfect recollection afterwards of what you did while on it.