I have a Monk and started Inferno a few days ago. I was struggling so bad at the beginning that I started farming for gold so I can go and buy decent items in the AH. I started Inferno with 350 buffed resistances and 30k life and 16k dps. Still I was struggling. My life would drop within miliseconds against elites. Normal mobs I had no problems. But as soon as I stumbled uppon an elite mob with fire or poison damage... oh lord.
Then I went to the AH and bought items... Resistances went up to 1200 buffed, DPS dropped to 11k and life dropped to 20k. What a difference that made! If anyone is struggling then go for resistances. Monk is easier to raise them as you can stack up one resistance and then use "One with Everything" and match all your resistances.