I actually think this area is very important, and you shouldn't just grab a generic template. This is one of the only areas where you will interact with your users outside of your site, and it can really make a difference in how users interact with your site.
The diction of the emails can give people drastically different impressions about your service. Also, the specific way you layout the messages can have significant impact on what people do with them (delete immediately, click on the right link, etc.). I have been in the position of having huge sample sizes on these account management emails so that I could test different messages. I can tell you from experience, changing one word here or there, link placement, color, fonts, etc. can all have a huge impact. Unfortunately, most people aren't in a position to do useful experiments.
Because of that, I don't think it is wrong to essentially start with a copy of a site you particularly like in this area. I wouldn't just pick any site though--I would pick one that is similar to what you want in terms of style and one you believe has tried to optimize these processes. Technically, if an email was really long and you copied it all verbatim, that could be copyright infringement. However, it is doubtful anyone is going to care. And it is more likely that you will change the emails and they will be short so that the copying really won't constitute infringement anyway.