tragictravisty said: yea, but you can't say they don't sound good...
Polyurethane and Nitro does not affect how a guitar physically looks so I dont understand ho a poly guitar could look "punk" you do understand that most vintage "punk" guitars where in fact painted with nitro...Vintage Fender's yes such as Kurts Jaguar and Comp Mustang where finished in Nitrocellulose...Steve Jones' Les Paul was finished in Nitrocellulose even the vintage guitars owned by Sonic Youth are painted in nitro...
The difference in Nitro and Poly isn't in looks but in tone, guitars finished in nitrocellulose dry out over time and allow the wood to breath more resulting in a more natural woody tone such as that found in Vintage Fenders and Gibsons. Polyurethane is more thick and plastic-based they don't allow the wood to breath and do not age over time they essentially stay the same forever. Poly is not a good finish for guitars imo, nitro is an awesome finish although its not a good thing for the environment totally. However guitars aged with polyurethane will never look "punk rawk" like this

My vintage Mustang is finished in nitrocellulose and heres a shot of the headstock notice the splits and cracks from the nitrocellulose aging over time, this will not happen with a Polyurethane finished guitar at least not in any of our lifetimes

To be perfectly honest a poly guitar is less punk rock because they are shinier and more pristine then a nitro guitar would ever be.