In the flower beds we prefer pine bark because thats what the wife likes.
In the veggie garden we use a lot of straw. Straw is more available, easy to irrigate through and tills under after the season. It can be a bear to remove weeds that may grow up through it.
My preferred veggie mulch is grass clippings. I can't get enough of them. I'd take them by the semi-trailor full if they were available.
I prefer crushed pine straw, but it has become very cost prohibitive for the amount I need, so, I use a layer of fine pine bark followed by regular pine bark. The fine breaks down a little quicker and adds organic material to the beds.
I use what I can get by the truckload inexpensively. I'm not sure it really matters so long as it is organic and breaks down year to year... I have a zillion pine trees and hardwoods so whatever falls, stays there. I buy truck loads of pine bark mulch or hardwood mulch and haven't seen much of a difference between the two. I can't see buying pine straw (needles) when I get a crop every year. It's just important to add more mulch every year and to add it pretty heavily -- don't skimp, a solid 3-5 inches holds the moisture in around the plant. I don't mulch to the stem/trunk, but I want the mulch to hold the moisture in the soil AROUND the plant, too. And if I can do anything to NOT water, I'll do it. City water is expensive!
I saw RUBBER mulch at a store and laughed myself silly. Mulch has THREE jobs, look "finished" and hold the moisture in and provide organics to the plants. RUBBER?????? hehehehe.