As above. No standard size in reality - but think practicaly. You need - ease of use - not worry about space and positioning of your portfolio (or asking one of the panel to hold it!) - A3 is optimum (unless prospective employer has specified otherwise).
btw - Gareth (Dot Design), the Guardian - BIG well done!
Totally agree with everyone else. A3 with work presented well using the plastic pockets. If you can get one with pockets on the inside cover that'd be useful too, especially as your career progresses. You'll may find yourself working on material such as brochures which you want to keep intact and pull out for the interviewer (or for whoever) to flick through. I've always found this to work well for me.
I actually got my A3 portfolio at a bargain price on ebay a while ago. It looks professional, has the sleeves, a cool strap and those handy pockets. Being A3 it's perfect in size. In fact when I left a previous design job they gave me a leather bound A2 portfolio case for a going away pressie. Have to admit in the 4 years since, I still haven't used it because it's too big.
I have an A3 box portfolio - much nicer than a ring binder in my opinion as you can pass work out around the table and get some fluid conversation going. The archival quality sleeves you can get are super smooth and protect your work from fading in the light also.
I have used an A2 portfolio in the past. Although it depends what you're doing, if I was looking for employment at a more digital agency and iPad 2 would do an awesome job (although perhaps out of a graduate's price range...). I've mounted stuff on foam board in the past and made custom boxes. Basically think beyond the 'standard', you've got to stand out and your presentation skills are very much part of it.
As I was reading some of the articles on getting employed & some of the tools we use – e.g. ‘graphicbreeze’ size of portfolio [really like the box by the way - linziloop:icon_smile: ]. It reminded me of interviewing a couple of upcoming designers applying for work with 2 corporates I represented.
One fellow [still going & Very Good at that] wouldn’t come to our office. He would only meet at his local hotel. :icon_thumbdown:
He looked like he been on the razzle all night.
His Portfolio was large A2 and very intrusive as we sat in a hotel foyer.
The work was clearly excellent, but lacked congruence.
The presentation was quite hap hazard.
The point is simple I would use him today (I have sent him work) but his attitude and appearance was so amiss at the time we passed over him.
He obviously could produce the goods but my boss (the paymaster) would never have entertained him.
So be available, be presentable and be open.
Use a A3 size portfolio
Plan and organise to ‘yes’ demonstrate your strengths but be congruent. Segregate into sections of different ‘projects’ clearly.
So keep it clean, simple. You are selling yourself as much as your work.
Box portfolio's seem to be very popular at the minute. They're the kind that my tutors suggest to get because they're interactive and engaging as linziloop mentioned (and the price surely implies you're passionate about your work).