Hey Asp, I really appreciate what you are doing with Gregtech 5, and I am looking forward for the things you plan to implement (research ftw).
One thing I love about Thaumcraft and I feel we need on Gregtech, are the new shinny things we unlock about every tier of research: Boots of the Traveler, the Tools and magical weapons with awesome effects, the flying chest armor, etc...
I think that this is what you're trying to do (I hope so), every tech tier could have some nice things aside processing machines, so I wanted to give some suggestions:
*Piston Boots: Low tech. Crafted from a pair of bronze boots, pistons, some springs, etc;
You charge it with steam at the boiler, and while equipped, you can use a hotkey to activate the pistons, giving a jump boost of 4 or 5 blocks. After using, It needs about 5 seconds to activate again (you can hear the steam or/and metallic sound when it's armed again).
With higher tech, you can make a module to equip on your boots giving about the same effect.
*Scuba helmet: Underwater Breathing. Last time I tried the Hazmat + air cells, (GT4) I was very disappointed, it used the air cells too fast! This could be only an helmet and an Air tank, with capacity to about 10 mins (or more with higher tiers).
*Auto crossbow: I am a FFVI fan, and Edgar's auto crossbow was awesome. It could use an electric engine and a have a battery slot, making about the same tier of the electric tools (could be available before the electric blast furnace). Less range and damage than a bow, but with incredible fire rate and cheap bolts so we can hold the trigger and make it rain bolts. Rain-bolts... hmm, I liked how it sounds;
*Iron Steve armor: High tech (endgame) - Not really iron, but made of and Titanium-gold alloy or something.
With thrusters, tiny rocket launcher and lasers, you know what I mean. You need a enter into a Multiblock machine with robot arms to equip/remove it, and uses A LOT of energy, probably a Fusion reactor would be needed. This is my dream. An hotkey to open the helmet visor would be cool too.
Thank you, and keep up this great work!