I have heard and read good things about the CILTEP (chemically induced long-term potentiation) stack mentioned above. I've used it before and found it so-so, but check it out if you want.
For a daily stack, a good fish oil, your racetam of choice (mine's usually a combo of piracetam and aniracetam, though I don't use it daily, use whichever you prefer), and look into something like Lion's Mane mushroom to increase memory capacity. Uridine would be a good addition as well. This would be a very simple, effective and cheap stack.
For energy and well-being, as well as improved mental capacities, there's nothing like a really dialed in diet and exercise regimen - regular, vigorous exercise, along with plenty of real, nutrient dense whole foods, lots of greens and clean grass-fed cuts of meat and eggs. Oh, and proper sleep. Kind of a boring statement, I know, but it by far has the most profound effects, so if you don't have this nailed down already, make that a goal. You could look into a good enteric coated SAM-e product, I've found it very effective for increased energy, motivation and mood, and it has a ton of other good benefits as well. We all like the magic pill solution, and I've found SAM-e to be a nice, reliable addition.
For the more hardcore study stack, add to your basic stack above caffeine and theanine. I don't know how you feel about using nicotine, either in gum, patch or vaporized form, but I used it as a gum to great success last semester for studying, taking a small amount during each study session and then again during the tests (state dependent learning). You could do sulbutiamine for the really intense, longer study sessions, but I don't believe it to be one of the more sustainable supplements, so keep that in mind.
Also, look into dual-n-back training if you haven't started already - you almost don't need any noots if you use dual-n-back as directed, crazy effective.
