My first one will be 3/32", but I'm just wondering how popular the 1/8" is among you guys?

I use both. On my conversion/beater I am using 3/32" and on the track bike I am using 1/8". I don't think one is superior to the other it just depends if you are using road vs. track components.

1/8" is pretty popular, but I think that's because people overestimate themselves. Many pro trackies use 3/32" without any problems.

I run 1/8" but sort of wish I'd picked 3/32" these days. It tends to be quieter and more available if you're running road cranks. My track bike and road conversion both have 3/32" rings and 1/8" cogs. My mountain bike features 3/32" all around.

A 1/8" cog was all that was hanging around when I built up the bike, so the rest sort of fell into place.

I run my chain with as little slack as possible so there's no slop when slowing or trackstanding, but this inherently puts more stress and wear on the drivetrain, so I'm running 1/8" just 'cause it's more reliable and lasts longer under these conditions.

3/32" on the road conversion

the track bike is probably going to be 3/32" as well, cause that's what I've got lying around.

I use 3/32 cogs and rings and 1/8 chain.

any particular reason why? doesn't that get pretty loud?

All 1/8".

1/8" with that honking shadow conspiracy chain on the street bike, 3/32" on the track bike.