I've avoided this thread till now. I just caught up with season 4...
HOLY FUCK
I don't even know where to begin. What an amazing season. The path that Walter White has taken is just so unexpected and so damn bloody brilliant. His descent into evil (lets be honest, pure and simple he is a bad guy now) has been a fascinating character study. I'll get this out of the way...there are a lot of holes in the Brock poisoning that even I had questions about after finishing the season finale an hour ago. What happened to the ricin cig? How the hell did Walt pull it off? Granted, I agree it was a hail mary but I hope the show does explain a bit of the "how he did it" later on.
I think my favorite thing of all season though was when Walt went to get the money to pay off the guy for the new identities and just starts laughing maniacally when he realizes he is just completely and utterly fucked since Skylar gave the money away. The way he was laughing in the background as Skylar was on the phone with Marie...brilliant.
Its funny because in the last 4 months I have been catching up to this show, I look back on my takes on both characters and I realize my perception is now completely different. Initially I loved Walt and hated Jessie's self destructive nature, but now I am almost abhorred at the depths Walt will go to "to win" and I am once again sympathetic to Jessie's inner moral compass and need to atone for the things he's done (Bravo Schwartz on the analyses, I totally agree with you)
In my mind, this show is one of the top 5 of all time at this point and there is only one character in TV that even comes close to rivaling Walter White and thats Vic Mackey.