Here's my take after spending some time there this year:
Accommodation - West End. It's a cool neighborhood that is walkable and has good food, cool bars and pretty girls. The CBD (central business district, Australian speak for downtown) has pretty girls coming and going from work in the day and at the after work type bars in the evening. The CBDs of Australian cities are generally more lively in the evening than the downtown areas of American cities which tend to empty after work. Saint James Street is also a cool area with good shopping for menswear if you need to step up your fashion game.
Best Cell Phone Provider - I use Telstra and have no issues, even in the rural Western Australia desert. Skip Vodafone.
Best Bank- Can't help there but I'm sure they are all comparable.
Fitness - Anytime Fitness is a chain of gyms that has locations all over the country and, as their name implies, is open 24 hours. I have been to a lot of them and in my experience they are basic facilities but clean and properly operated. There is a squat rack. There is not a basketball court. I'm not sure how many basketball courts you will find in Australia.
Online Gaming - Can't help on this one, but there are plenty of girls out and about in the neighborhoods that I mentioned above so I would say skip it.
Nightlife -
Timeout Brisbane is a good resource for what is new and cool and good. The West End has some good cocktail bars that are kind of hipster-ish but not annoyingly so. The CBD has some clubs but to be honest they seem to be mostly full of trashy and chunky Queensland girls who roam the streets at night in big ugly herds. Australian guys also like to punch people in the face after midnight. For me, the West End cocktail bars are the best bet. They can be hit and miss in terms of crowds so wander around and poke your head into a few. A place called Sling has a tiny little bar in the front with a huge open area in the back, worth a look. Also, be forewarned that you can easily spend $17 on a cocktail. Australia is fuckin expensive.
General - As an American I have noticed that my accent goes a lot further in Brisbane than in Sydney or Melbourne. In Sydney it can be hard to find an actual Australian person in some areas like Bondi Beach, it's a very international city. And residents of both Sydney and Melbourne think of themselves as quite cool and are therefore hard to impress without implementing some advanced level social game that is beyond the scope of this post. But Brisbane is much less diverse so a foreign accent get noticed much more, often being received with wide eyes and big smiles. Generally, Australian girls are up for it. They are approachable and have good attitudes, at least in terms of having a drink and chatting and transitioning easily and quickly to the bang. I have not dated any for longer than a couple months but due to their largely gender neutral culture and willingness to bang I suspect the girls are not very trustworthy on a longer term basis. But it is a nice place. The warm weather and beaches make for a generally fit and relaxed and attractive population of white people. Combine the good aspects of California (beaches, weather, sophisticated cities) and the UK (beer, functional Anglo business environment) and remove most of the bad (crime and immigrant overpopulation in California, horrible weather and ugly girls in the UK) and you have Australia. Australians seem to all have well paying jobs and a very large middle class, perhaps similar to what America was in the 1950's in terms of income distribution, so the playing field is fairly level. They do not seem to understand sarcasm very well, so a positive and fun attitude is your best bet. It took some time for me to figure this out and shed my pseudo-hipster brooding game. Basically they all like to BBQ, go to the beach, drink and bang. I've had more than one Aussie guy with a big smile on his face ask me if I've "had a crack" at their women. I have been happy to say yes.