More extensive syntax coloring, so you can easily recognize different file types. (after using plain dired for 10 years, the first few days i found the colors distracting, but now i prefer it.)
Press w to copy file name. Works with multiple marked files too. Useful when you work with bash or shell tools a lot.
F to open all marked files. (nice!)
Use menu 〖Mark▸Omit Marked〗 to omit some files. (useful especially if you use “find-dired” but don't want a subset.)
To install, just place the file at 〔~/.emacs.d/dired+.el〕, then put this code (require 'dired+) in your emacs init file. Optionally, call “byte-compile-file” to make it load and run faster.