I didn't go at MG, so I had a slightly different experience that avoided the major crowds... (Dec '06)

I had a blast in SYD. Went to most of the above-mentioned other than Slide which had special events when we considered going. It definitely is popular for a Thurs/Fri/Sat, I'm not sure if it's open other days.

Also, ARQ is the place to go on a Sunday night - completely packed deep into the morning.

My personal favorite was the Colombian in the early afternoon, sitting at the spot that has an open-air view of the street. A great place to while away a few hours having a beer and meeting locals filtering in for a happy hour drink.

If you're headed out to SYD or live there, consider me envious.