I haven't watched the show but I heard an interesting theory on how it's going to end for Walter. The last episode is named "Felina". According to the director it's just the word finale scrambled. However, in the Marty Robbins song "El Paso", the person in the song returns to El Paso to see the woman he loves, who is named Felina, even though he knows he will die if he does go there. The person does go back to Felina, gets shot by the law in El Paso and dies in Felina's arms. The person who had this theory believes the same will happen to Walter.
[youtube=425,350]http://www.youtube.com/watch?v=kIHRgisdbeY[/youtube]