Everybody's got libraries they use on a regular basis. I use jQuery in almost every web-app I build, for example. Tools like Yeoman can do all this for you, but that's not always handy, and I often end up copying my downloaded version of library (which I have to remember to update) into my new project folder.
I've been using Sublime Text 2 for everything for a while now, but I just found out about the Nettuts+ Fetch package. Simply add your libraries to the json settings file once, and then you can download the latest version to your current project or a new tab by typing a couple of letters and pressing enter!