I prefer to think that Lelouch did indeed die, his death would be more symbolic that way, plus if he was immortal he would've risen again almost instantly.
He paved the way so that he would be hated, that all things wrong with the world should be blamed by him, so that hatred would die with him, paving the way for a future that Zerozaku, Nunnally, Orange-kun, Anya, Ohgi, Kallen, and the rest of the world would see through.
Also, one thing to note, does anyone else find it hilariously awesome that Orange-kun now works on an Orange farm?
All jokes aside though, Orange = GAR now? After all he survived a whole shit load of things from surviving the destruction of his frame by Kallen's Guren, surviving crushing depths with C.C. pushing him down into the depths, surviving Lelouch's Sakuradite disruptor and bleeding manly tears, AND surviving several explosions in the final battle and jumping onto Anya's Knightmare Frame.
That is just awesome right there.
What do you guys think?