I've always thought that doing 5dd and such was a bad demonstration of Vi(m) since I never know how many lines to delete. I'll just dd multiple times. More powerful vim commands are like daw (delete all of a paragraph), di) (delete inside of a set of parentheses), and dtX (delete until the character X).
daw deletes the word you are in (delete a word). But dap deletes a paragraph. And you can tell vi what you mean by "word" and "paragraph" (I think) in your settings file.
I tried this for a while but it never clicked for me. I prefer using semantically-meaningful groupings like paragraphs or parentheses, it just seems nicer. And relative line numbers wouldn't make, say, 5dw any easier to count.
You can use: df<char> to delete forward (including char),
dt<char> to delete forward until char. (excluding char)
d/<search><Enter> to delete until search pattern is found
In case you wish to type immediately after deleting, replace 'd' with 'c' in the above.
