It's true that few servers even provide that kind of bandwidth. That's why I personally stick to 1 Gbps and save a few bucks. But I have friends who use the 25 Gbps e.g. for off-site backups (a NAS at the office for home backups, one at home for office backups). Stuff like game downloads or uploading large media are also sometimes mentioned. And you can really benefit from the parallel connections in P2P stuff.