Well the first link is the exact same one I already have:

...which cracked a tooth and smashed a pawl, seizing my pedals while I was riding in the rain. So I'd like to try something else in the hopes of it lasting longer, but the second link is $70, which is a lot of money.

So I'm looking for other options...I'm also not opposed to converting this bike to a fixed gear, but I'm not sure where to get a crank with a 67mm BCD and I don't want to have to fabricate my own parts.