Originally Posted by Nightshade

"The other factor is weight - I'm almost 300lbs, are there any pedals I should stay away from weight-wise?"

Stay away from clip in or toe clips since you need full range of foot motion to be safe on a bike.

Any platform pedal on this page would serve you well at your current weight.

http://www.sheldonbrown.com/harris/pedals.html

I have the rubber block pedals on my bike and they feel just right dampening road vibes under foot while ride!!!