Honestly, I am not lured by any particular company based on what it does or it's image or even it's culture. Because a company does X, it doesn't mean my job at that company will be good. Also there might be super interesting roles hiding in boring looking companies, like for example a pension company or a staple manufacturer.

However to answer the question as best as I can, doing a CS PhD would be the most exciting thing - especially in those moonlight months at the beginning when you are exploring the space and learning. Maybe less so when writing the dissertation!