The characters for extended regular expressions are invaluable; is there a way to turn them on so that I don't have to escape them in my Vim regex, much like the -E flag I can pass to grep(1)?
Do :help magic in vim and you'll see there are four levels (very magic, magic, nomagic, and very nomagic) but only the two central ones can be set globally (the default is magic, and with :set commands you can only toggle between magic and nomagic); start your RE with \v to make all the rest of it "very magic" ("all ASCII characters except '0'-'9', 'a'-'z', 'A'-'Z' and '_' have a special meaning") -- but that applies only to that one specific RE!-)