Should an artist have serveral different portfolios?

Example - Say a freelance artist has a booth set up at a Arts & Crafts Festival selling artwork. Many people are stopping in and looking at the prints and originals that are displayed. Suddenly a person approuches you and it's a gallery owner wishing to get to know you and hopefully striking a deal. They ask you if you have a portfolio.

...What do artists do in general? Do they have just one portfolio for all situations? or many, each one for particular uses? What other situations do artists get into where they need a portfolio? Any tips would be a great help.

I am a graphic designer. My client base ranges from Churches to Night Clubs.

Depending on the client I will provide them with different examples of my work.

If I have a meeting with a church to show them samples of my work-I will remove the Rave flyers and club flyers and show them more conservative things such as real estate brochures or more family oriented designs.

On the other hand-if I have a meeting with a Night Club who wants flyers for their all-night techno party, I'll probably remove the church and family stuff from my presentation.

Regardless of what you decided to put in your portfolio...if you're good at what you do the client would be foolish to not hire you based on your clients and what items are in your portfolio. But, keep in mind that there are many foolish people out there.

my lovely and talented wife has three portfolios, one for illustration, one for graphic design and one for murals, and they are all different...she could do a fourth and fifth also one for her watercolours and one for her collages and burlap paintings.
i have three portfolios, one for my photography one for my faux finishes and one for my artwork (mixed media/gilt plaster)
sometimes (and only some of the time) more is o.k.

I think the type of portfolio in this situation would be a 'throw away' Basically its a booklet with examples of your work.
I'm heading into the animation field so we do DVD's which has a copy of our best animations as well as examples of our other fine arts and cartooning stills.
We've also been suggested to print 12-15 page booklets with examples of all our best work.
If you submit a throw away and get brought in for an interview then you would have a full sized portfolio with original pieces in it.

variety is not necessarily wrong. if you have a constant in your work it will only make you accessible to different markets. It is up to you if applying your fine art to a "coke" ad makes it devalued. (if your hip dont follow the masses)
intelligent people talk about ideas. average people talk about events, less than intelligent people talk about people.