iv'e tried it all over the years. everyone has different prefs. but this is mine:

i like the christophe double gate PLASTIC toe clips. they dont hurt my sneaker clad feet when cinched down for breakless urban riding, and the dont make a horrible scraping noise against the pavement. also, stepping on them doesnt crease them and break them like alloys. they double cate is comfy, and doesnt shift around my various sneakers.. gotta say.. these new vans toe clip specific shoes are fresh.

i also prefer nylon straps.. again, christophe is my fav.. but i recently bought some orange pake' straps from my LBS (20/20 cycles). the pake dont seem to have the same grip as the nylon christopes.. but they are good enough, and are bright as all get-out.

leather is expensive, rot in the weather (it;s seattle) and in my exp. doesnt hold like mylon. ive used lots of different brands.. although i cant remember spending 100 for any.. maybe i should try expensive ones.. but i doubt i will.

let me know if anyone tries the polish vegan dbl straps from king kog (awesome shop/people).. the clasp looks not so fresh.. hopefully im wrong, cuz i'd like them to be good.
ok. that's my .02$