Feel free to link me to a mod that adds the GregTech computer, fusion, thorium and plutonium, the centrifuge, etc, without all of his screwing around with other people's mods though.
That "etc" is awful big. People see the machines, but fail to recognize the massive potential game changing effects aluminium and other items GregTech adds to the game can have. Good changes, IMO.
Aluminium is primarily processed out of bauxite, but the easiest source is clay. (Which if you're near a red cobblestone biome or mystworld is sickeningly easy to acquire). Just like in real life, there's a technological hurdle to overcome to get the aluminium (you need an industrial electrolyzer) but once you have it, it can change the world - and in the process make some things much easier. Because it can be used as an optional replacement for many (not all!) recipes for iron, refined iron and tin. For some recipes, notably the advanced alloy recipe, when aluminium is used you can get more out of the recipe and thus save on other metals to get the same output.
Electrum has no technological hurdle to overcome and so is available as soon as you get a macerator or pulverizer. You mix one gold and one silver dust together for one electrum. When Electrum is used in electronic circuits / advanced circuits / class fiber cables (all things you use a LOT of, over all) you get more output for every input and thus save on all the other materials. Low on copper? Use electrum in place of redstone, and you get two circuits for the same copper cable / refined iron as for one normally. It replaces redstone in advanced circuits for double the effect as well.
Silicon plates. Everybody cries about them because they're needed for the solar panel (Rightly so because it makes that one recipe too hard, IMO) but fail to see that they can replace the electronic circuit in the *advanced* circuit recipe. You can jump directly to the advanced circuits, without using copper wire on the normal one. And again, if you use electrum instead of redstone, you get 2 advanced circuits.
Magnesium dust plus a rolling machine gives you plates that can be used to make windmills. Except, this recipe gives you *two* windmills per generator + two magnesium plates. All you need to get magnesium is something to grind marble to dust, and an industrial centrifuge.