Seems like a lot of people have trouble with this, so I figured I'd just write a shitty one up and see if it helps anyone.
Unlike most mods, Gregtech doesn't have a simple .ini file, it has it's own folder in the config folder housing several .ini files, most of which(all but BlockItemIDs.ini) will affect recipes or other features in the game.
TLDR:
Forestry Bronze: Gregtech.ini, Features, ForestryBronzeNerf=false fixes it.
EDIT: It appears that in 1.5.2 Forestry probably reduced it's bronze recipe to 2 bars for every 3 copper + 1 tin on it's own, and Gregtech has removed the config option as it is now irrelevant. Source: I opened Magic Farm modpack to check myself.
"My machines are randomly cutting off and destroying my items!": Gregtech.ini, Features, ConstantEnergyMachine=false fixes it.
"Where's the mass fabricator and how am I supposed to make this ridiculous matter fabricator that I hate/costs way too much EU to work/Costs iridium to make when you need it to make iridium": You can alter the EU cost of the Matter Fabricator in Gregtech.ini, features, MatterFabricationRate. If you just hate the entire concept, you can re-enable the Mass Fabricator in Recipes.ini, IC2recipes, change to MassFabricator=true to enable it. You can also opt to increase the Iridium spawn rate in gregtech.ini, worldgeneration, IridiumProbability. I personally play with mine set at 60, the "20" works out to one in 5 chunks somehow or another.
"wtf my quarry needs a drill which needs titanium which needs an industrial blast furnace? WTF?!?!": You can disable the quarry requiring a diamond drill in Recipes.ini, usefullrecipes, set ExpensiveBCQuarryRecipe=false to fix. If you're just here to get the drill, you can remove the titanium cost by going to Recipes.ini, usefullrecipes, set TitaniumDiamondDrill=false to fix.
"wtf why does the iron drill/chainsaw require steel all of the sudden?" You can go to Recipes.ini, usefullrecipes, set ElectricSteelTools=false to fix.
"Why can't I make mixed metal ingots?": They require a rolling machine to craft by default. You can change this back by going to Recipes.ini, usefullrecipes, set MMIngotOnlyRollingMachine=false to fix.
"WTF HAPPEN TO MY SOLAR PANEL/WATER MILL/WIND MILL RECIPES? WTF IS MAGNESIUM PLATE?!!?" Each has their own setting, head to Recipes.ini, usefullrecipes, set ExpensiveSolarRecipe=false to fix solar panels, ExpensiveWatermillRecipe=false to fix water mills, ExpensiveWindRecipe=false to fix wind mills.
"What is the deal with these refined iron plates?" That is Greg's new plate bending machine thing. Apparently he changed a bunch of IC2 recipes to require the plates for some reason without actually putting a config option in to disable it. If you want the old recipes back without having to ditch his entire mod, make sure to let him know here: http://forum.industrial-craft.net/index.php?page=Thread&threadID=7156 that you want a config option for it
Unlike most mods, Gregtech doesn't have a simple .ini file, it has it's own folder in the config folder housing several .ini files, most of which(all but BlockItemIDs.ini) will affect recipes or other features in the game.
TLDR:
Forestry Bronze: Gregtech.ini, Features, ForestryBronzeNerf=false fixes it.
EDIT: It appears that in 1.5.2 Forestry probably reduced it's bronze recipe to 2 bars for every 3 copper + 1 tin on it's own, and Gregtech has removed the config option as it is now irrelevant. Source: I opened Magic Farm modpack to check myself.
"My machines are randomly cutting off and destroying my items!": Gregtech.ini, Features, ConstantEnergyMachine=false fixes it.
"Where's the mass fabricator and how am I supposed to make this ridiculous matter fabricator that I hate/costs way too much EU to work/Costs iridium to make when you need it to make iridium": You can alter the EU cost of the Matter Fabricator in Gregtech.ini, features, MatterFabricationRate. If you just hate the entire concept, you can re-enable the Mass Fabricator in Recipes.ini, IC2recipes, change to MassFabricator=true to enable it. You can also opt to increase the Iridium spawn rate in gregtech.ini, worldgeneration, IridiumProbability. I personally play with mine set at 60, the "20" works out to one in 5 chunks somehow or another.
"wtf my quarry needs a drill which needs titanium which needs an industrial blast furnace? WTF?!?!": You can disable the quarry requiring a diamond drill in Recipes.ini, usefullrecipes, set ExpensiveBCQuarryRecipe=false to fix. If you're just here to get the drill, you can remove the titanium cost by going to Recipes.ini, usefullrecipes, set TitaniumDiamondDrill=false to fix.
"wtf why does the iron drill/chainsaw require steel all of the sudden?" You can go to Recipes.ini, usefullrecipes, set ElectricSteelTools=false to fix.
"Why can't I make mixed metal ingots?": They require a rolling machine to craft by default. You can change this back by going to Recipes.ini, usefullrecipes, set MMIngotOnlyRollingMachine=false to fix.
"WTF HAPPEN TO MY SOLAR PANEL/WATER MILL/WIND MILL RECIPES? WTF IS MAGNESIUM PLATE?!!?" Each has their own setting, head to Recipes.ini, usefullrecipes, set ExpensiveSolarRecipe=false to fix solar panels, ExpensiveWatermillRecipe=false to fix water mills, ExpensiveWindRecipe=false to fix wind mills.
"What is the deal with these refined iron plates?" That is Greg's new plate bending machine thing. Apparently he changed a bunch of IC2 recipes to require the plates for some reason without actually putting a config option in to disable it. If you want the old recipes back without having to ditch his entire mod, make sure to let him know here: http://forum.industrial-craft.net/index.php?page=Thread&threadID=7156 that you want a config option for it