Mine would be Valentina Lisitsa, and Rachmaninoff!
That would've been hard to guess.
But it would be fine if Rachmaninoff couldn't show up because of traffic, and it was just Valentina Lisitsa and I! She's like a female reincarnation of Rachmaninoff! So that would really be Valentina Rachmaninoff! 
I'm not sure if this is creepy or not...
As interesting as Rachmaninoff is,
everyone's going to be going to dinner with him, so I don't want to bore him! Plus, I can just talk to all the people he did go to dinner with in order to learn more about him. Bach, of course, would also be a lot of people's option, but he didn't speak English, I don't think (fact check on aisle two?).
Sooooooooo...
I'd take Sviatoslav Richter and Krystian Zimerman. I'm not positive Richter spoke English, but I assume so. If not, it'd be an even more interesting dinner party, wouldn't it?