Use the authenticator. Use the authenticator. Use the authenticator.
If I haven't made myself clear,
Use the authenticator. State of the Game:You're going to have a lot more fun with the game if you pretend that Inferno, hardcore mode, the RMAH, and even the AH don't exist. (Unless you're like me and making money from the RMAH) Once you get to Inferno, there are certain ways the game HAS to be played.
I've nearly paid off my copy of D3 through the RMAH, and played 3/5 of the classes to level 60, and almost done with the last two. If you want some advice, read on and feel free to ask questions.
1.03 was aimed to nerf the prevalence of farming Demonhunters. Unfortunately monks got caught in the crossfire.
Demonhunter: Vastly overplayed, almost everyone has one. All you need is a great weapon to farm as a glass cannon, and built well is very survivable. Because everyone has one, gearing one through the Auction House is a pain in the ass. Seriously. Have fun competing with everyone. On the other side, great drops for them are worth a ton of money. One of the only classes I haven't spent too much time on because I'm always playing with them anyway.
Monk: Pretty much nerfed into oblivion because they were so broken before. Fun class to play before inferno, but if you go inferno be prepared to stack All Resist and One With Everything resist, otherwise you'll melt. Ridiculously expensive to gear and very difficult to get through inferno. I'd say it almost isn't worth it.
Barbarian: Stack all resist, strength, vit, life on hit/lifesteal... Still able to tank with the right build. Unfortunately you have to use the right build. Everyone complaining about barbs not being viable in inferno are not using tank builds. Unlike demonhunter and other classes that can kite, you're in the face of mobs hitting for 30k+ if you have no resists, so get resists and armor.
Wizards: Crit wizards, surprise, surprise, are still broken after nerfs. You can
youtube videos of people permafreezing Diablo in Inferno and killing him with ease. Critical Mass + Wicked Wind rune on Twister, 40+% chance to crit, perma-Diamond Skin, mobs are perma-frozen while you dink at them.
Witchdoctors: Zombie Bears are so good. So good. Although because of various builds viability, the class might as well be called Vision Questers, or Spirit Vesselers. Every endgame build involves activating vision quest in some way, and then spamming.