Seconding the rOtring 600 - I got mine at the start of university, and it doesn't show any signs of stopping near the end of my bachelor's now. Though, you do

Seconding the rOtring 600 - I got mine at the start of university, and it doesn't show any signs of stopping near the end of my bachelor's now. Though, you do need to carry it in a case of some sort, because the tip doesn't retract.