The best players on GTA Online realise that if they're going to commit a robbery, they should either go big or go home. A proper heist takes planning and a good, committed crew.
LetsPlay here has the right idea -- this is the most elaborate, ridiculous heist I've seen on GTA Online. Granted, for all the organisation they bank on, things don't necessarily turn out the way they hoped -- and that's ok, because the lack of 'professionalism' is exactly what makes this worth watching. Plus, everyone knows that the best part about heists is where they go wrong.
The video is rather long and you might not have time for it all, I know. The first six minutes or so are the set-up, explaining how they hope things go down. You should watch at least a bit of that to get a sense of how meticulously they thought it all out, and then skip ahead to see the actual heist go down.
Kind of makes you hyped on the upcoming multiplayer bank heists for GTA Online, no?