I only have the one "giant" app but I'm still at 7GB+ of apps. Stuff adds up quickly. Magazine content is getting increasingly large so it's not unusual to have 4 or 5 magazines adding up to 1GB. I don't store videos on my iPad, I just load a few at a time and then refill with new content. Even then I know that 16GB would be too limiting.
The OP can control only so much by keeping his media and docs at a minimum. It's tough to anticipate your app needs over time, so saying 16GB is fine today is possibly short-sighted in that respect.