[Robbie J]

Okay, I'll answer my own question... I managed to visit the 'Cloud 9' bar on the rooftop of Rydge's Hotel at the International Terminal. It's small-ish, but I had a long chat to the young bartender, a Nepalese man, and he said the places never gets too crowded.

Most of you would know this rooftop area as the former Rydge's airport viewing platform, which it still functions as, but now it has incorporated a nice wine bar.

Prices weren't cheap -- they wanted $12 for a local Australian beer -- but that's probably not surprising at the airport or in an upmarket hotel or in a city like Sydney these days.

The main bar area has floor-to-ceiling glass windows, offering good views of the airport's runway activities.

The outside viewing area has a glass barrier, rising to about 7-foot, but people were standing on the seats and benches that run along the glass barrier so they could get an unobstructed view of the airport, with no interference.

Overall, it was a nice spot to enjoy a drink and do some casual spotting.

Most of the patrons in the Cloud 9 bar seem to be travellers who are staying at Rydge's, not spotters. They're always good company for a conversation about travelling and airports.

For me, the highlight was at twilight when the bar staff dim the lights. The combination of low-light inside the bar and all the twinkling neon seen on the tarmac and the terminal was a beautiful sight.