Caffeine and L-Theanine is regarded as one of the most efficacious Nootropic combinations. A 2010 Dutch human study, The combination of L-theanine and caffeine improves cognitive performance and increases subjective alertness, suggested consuming Caffeine and L-Theanine in approximately a 2:1 ratio. From it's abstract:
"The combination of moderate levels of L-theanine and caffeine significantly improved accuracy during task switching and self-reported alertness... and reduced self-reported tiredness... There were no significant effects on other cognitive tasks, such as visual search, choice reaction times, or mental rotation. The present results suggest that 97 mg of L-theanine in combination with 40 mg of caffeine helps to focus attention during a demanding cognitive task."
This stack is one of my favorites and I consistently start my mornings like this...
My Lifehacking Morning Beverage Regimen
Before I go to bed the night before I leave fill my glass water bottle with water and drop two teabags in it, green tea and usually another tea variety with a little better taste, like Flor de Jamaica.
Before bed I also put the coffee grounds and the water in the coffee maker. Then when I wake up all I have to do is the hit the button on the coffee maker.
While the scent of the brewing coffee tickles my olfactory pleasure centers, I pour the tea in a glass, add some extra powdered L-Theanine, for a kick of creative energy, then skull the glass of tea to down whatever other Nootropics I'm taking.
Then I pour my coffee, begin to sip the dark nectar to wash away the nasty taste of any other Nootropics I've taken (Like Phenylpiracetam... that stuff tastes like angry fire ants!), then I get shit done.
Modafinil
Coffee and Modafinil is one of my favorite combinations actually, since I don't find Modafinil particularilly energizing and it takes sometimes as much as 3 hours to kick in for me I will wash them down with the dark nectar. The hardcore cognitive enhancing effect of Armodrafinil in combination with the stimulation of caffeine can be paranoia inducing for some people so go easy on the dosage.
Piracetam
This is actually the one Nootropic that makes me go off coffee, the energising effect of Piracetam is so much more acute than coffee's and in my experience the two really don't compliment each other.
Aniracetam
This Racetam's Ampakinic effect is nicely complimented by Caffeine.
Caballo
This mixture of pharmaceutical grade Racetams goes,
Phenylpiracetam
Another awesome focus drug that's not very energizing, is nicely complimented by coffee. Coffee seems like the only thing that can actually wash away the terrible taste of Phenyl.
Phenibut
I've tried coffee with Phenibut and I have to admit it's a pretty awesome cocktail for a crazy sleepless night, if you are into that sort of thing...