The first two are very useful, if you kill bugs for a living (read debugging freak).

• NERDCommenter
  ‘NERDs use real editors (VIM Flame flame…) and Comment their code’. This plugin helps comment code in almost all languages you program in. The way: select ‘n’ lines in visual mode(or punch in a number in normal mode), use ‘,cc’ for normal commenting of that code. ‘,cu’ will uncomment the lines. ‘,c<Space>’ will toggle the comment status. ‘,cs’ does magic, try it!
• Taglist
  This is your friend for browsing those 1000x lines of legacy code. All it does is: creates a split window and shows the macros, functions, variables etc.. You can C-w (ctrl+w) to the split window and start jumping through the code. Ofcourse, I agree with the die hard ctags fans. CTags is the ultimate thingy! I prefer not using my best weapon(ctags -R *.cs) against a single progam.cs which has damn 3000 lines of code (its reality! spare me, I din’t write that program ). So here’s how to bring down the taglist to single key:
  ! put this in .vimrc/_vimrc
! press \tt to toggle taglist on/off in normal mode
nmap <Leader>tt :TlistToggle<cr>
• Timestamp
  This will add “time” dimension to your source code. First time you create the file, add these:
  Created: TIMESTAMP
Last Modified: TIMESTAMP
  Rest assured for the life of that file. Every time you save the file, Last Modified will get updated. For those lazy guys, this is a tool to measure your level of procrastination.

What would be your “three” should-use vim plugins?