I'm a student, so I write a lot, and the rOtring 600 mechanical pencil is incredible. I've not used a single genetic #2 pencil since I bought it last year, and I don't plan on using one ever again. The feel of the pencil is super solid, and rOtring also handles small lead sizes much better than any other brand I've used (especially .35mm) which means I rarely break my lead.

Other than the pencil, maybe my Peak Design everyday backpack? I got the v1 used on eBay for ~$100 and I've used it for maybe two years now. It's still a decently student-specific purchase, though.