Though, it is useless to say "don't go overboard" with things in FTB, choose a project that is challenging in the sense that it would require a lot of resources, but would do something very useful to you. An over-sized AE system would do nothing for you. It would be similar to buying a super computer to run tetris. That would be an example of "because I can", rather than "because it is useful to me".
Similarly to my situation, where I choose to build 12 steam boilers to power, 216 engines, into 60 magma crucibles, to power 96 thermal generators. I've vamped up my matter fabricator energy input to about 2k EU/t on average. It peaks at 3.5k during the day and when my legacy lava system is in purge status. This project required a vast amount of resource/time, but provided me with something incredibly useful. I am generating UU at twice the rate I did before.