I take toe straps seriously. Still ride them on more than half my bikes. I will not go down big hills on a fix gear on anything but traditional pedals, clips and straps because I never, ever want one foot to detach when my RPM is 200+. (And at that RPM, I have no idea how straight I am keeping my foot.)
Now, I steer clear of the braided straps like ryansu is showing, They slip reliably when you pull hard going uphill. If they slip enough, your foot pulls out and you are walking to the top of the hill. (Try starting on a fix gear on a steep pitch. And that first pedal stroke after you get your foot in is one of the really big pulls you will do, If that strap let you down once, it is near certain it will again here.) Drillium dude shows a very respectable strap. (Give Alfredo my best.) And Mad Honk's use is one of the approved ones.
I've stopped chasing the good straps like Alfredo and his cousins. I now go the local leather shop and buy 1/2" strips of quality leather. Fixed price. Length is what the hide is, usually ~6'. Pop rivet that to a quality buckle. These don't last as long as the really good straps but they are far easier to deal with and I spend a lot more time on new, good straps.
Haven't strapped a sewup to my seat or toolbag for quite a while but it is going to happen again in the not too distant future. Most or all of my wheels will be rebuilt sewup when the rims die. (And this being lava dust Oregon and all my wheels rim braked, they will.) I also strap the chain whip to the TT of my fix gears with straps that I make up to length for the job. Completely secure and the whole stop to change out a cog is about 5 minutes.
Ben