What can I do with all my EU?
On my Tekkit server I have several solar arrays and a nuclear reactor producing tonnes of EU, and most of it if going into storage and rarely used en masse. Aside from a mass fabricator, how could I use this EU in a productive way?
That's about it: a mass fabricator. Anything less doesn't need all that power, since the draw is so low that it might as well be free. Even then, once you've made everything you want from UU matter, you'll still have more power lying around than you need to keep your godlike gear fully charged.
Though, if you have the EU to power a small town, maybe you could start using it like that. Build things like street lamps using Luminators just because you can waste the power on something so frivolous. The wiring and building challenge of a huge power grid (and the aesthetic structures to go with it) may be worthwhile all its own.