In my opinion, clipless pedals are always a good thing.  With the type of riding that you are doing your best bet would probably be a mtn bike pedal/cleat setup.  Mtn bike shoes are easier to walk on, and are usually very quick to unclip.  You can get pedals that clip on one side, and have a platform on the other, this way you can not clip in if you're in an area where you want to be able to drop a foot with no worry at all.

As a side note, there's an entrant in this years  TT's(500 solo division) from Denmark who recently completed the Last Chance 1,200k, that rides with platform pedals. No truth to the rumor that he wears wooden clogs as his cycling shoes.  

I rode my EZ-1 without clipless pedals for 2 years.  I still ride my Rans V-Rex without clipless pedals and did RAGBRAI on the Rans this year with no problems.  I want to be able to get my foot down during traffic quickly and I'm not that quick in clipless.  My DF has clipless as does my trike.  Try both and see what is the most comfortable for you.

I rode multiple century and double metrics on my Stratus with platforms and "regular" shoes, and a couple hundred miles on an EZ-1 with platforms without any problems aside from a lack of fitness from not riding a bike in a while. I'm trying some toe clips without  straps (I think they're called "mini clips") on a set of modified platforms (the "ghetto pedals") to see how they work.

A lot of folks like powergrips http://powergrips.mrpbike.com/ as well.  I've never tried em, but some people go on and on about them.

I ran Power Grips on my trike for a couple of years. For me, they are to much trouble to get in and out of for a recumbent bike. I ran them on the trike to try to get around the problem with my broken feet and they did pretty well until I developed enough power using regular shoes that my arches started hurting. I dropped them when I figured out how to move the cleats back on some mtn bike shoes that had adequately rigid soles.  
 
I commuted pretty much every day for years on several different types of bikes and when you do that, you develop the understanding that your bike is a commodity, that you chew things up and they have to be replaced. It's an expense but a really cheap one compared to a motor vehicle. Pretty much *anything* that makes life substantially easier for commuting is most likely worth doing, and using clipless pedals was one of the most advantageous things I did, whether is was my road bike, the trike, a mtn bike or the recumbent bike.
 
They make life far easier to do hard/fast accellerations in heavy start/stop traffic, they provide for more power/speed when cruising because that's primarily using pull muscles, and on bikes that have potential heelstrike, it makes life far easier to do very tight turns in poor road conditions. Sure,  you can do without out them, but I'd rather run 120psi tires at 60psi than do without clipless pedals.
.