I'm a MacVim user and a TextMate convert. I use the Vividchalk theme, which is basically a modified 'Vibrant Ink' theme (from TextMate).
I've remapped j and k to gj and gk so for long, wrapped lines, I can navigate using j and k.
I've mapped ; so that it does :noh - removing search highlighting.
I've remapped / and ? so they bring up /\v and ?\v - it puts it into very magic matching - see :help magic.
I've customised the ruler format so that it shows HH:MM. This is because I often use completely full-screen Vim for note-taking in class or on the train, and it's nice to be able to see the time.
As for plugins: a bunch of syntax highlighters (Scala, Wikipedia), rails.vim, TwitVim and snipMate - so I can just type things like 'sout', push tab and it expands it out to System.out.println(""); and makes it so that the cursor sits between the quotes. I've written snipMate snippets files for some custom MediaWiki templates I use frequently and installed one for Scala.
I'm tempted to add vcscommand as I use git.