I bring:
- A portfolio like this
- A list of typed questions I have to ask (in the portfolio)
- A couple extra resumes
- A nice looking pen (ie not basic bic pen)
- Supplemental material as necessary (portfolio, information about the company, printed things such as their mission/vision/etc, project plans/suggestions, other stuff like this)
The portfolio lets you bring everything else, store stuff they give you, and look more prepared. For $10 to $20 you can make yourself look far more professional and it helps avoid the "what do I do with my hands" problem (hold the portfolio!).
Typed questions lets you say, "I had a few questions I was hoping to ask, you have covered some, but would you be answer the others?"
I've made use of my extra resumes a ton. It's always really helpful to be able to look at your resume when someone else says, "tell me about some of the stuff on your resume." You don't want to blank on what your resume actually says.
The pen is obvious, but, make sure you don't fidget/spin it.
Supplemental material is optional but beneficial. At my last interview I brought a typed up, less than one page, "here's what I'm assuming the expectations for 30, 60, 90 days are" document I put together, which allowed myself and the interviewer to talk about this as if I already had the job which absolutely helped sell the job. "Here's what my assumptions about my first few months and expectations, how well do they line up?" is a great question to ask.
A warning - don't use a phone/tablet unless you are confident you will be seen as taking notes and not showing disrespect (or willing to take that risk). Many, many people will see this as disrespectful even if you do the same as taking paper notes.
This seems unfair and indeed it might be. But unfortunately you play by the rules of the interviewers, not what you want, and if you aren't willing to make that gamble, don't make it.