[elephantine]

If you're splurging, I'd highly recommed the Quay Grand Suites which are very close to the lovely botanical gardens and all major sights. Carseats are now compulsory only for kids under 1 year old: see http://www.rta.nsw.gov.au/roadsafety...lts/taxis.html
Kids over 1 yr old need only be restrained with the regular seatbelts, but given this is not the safest option, you could always call/wait for a taxi with carseats. Melbourne is a lovely city as well, though Sydney to Melbourne is quite a long drive (at least 10 hours from recollection) - might want to fly instead or drive somewhere closer? The Blue Mountains, Southern Highlands and Hunter Valley vineyards are all short drives away.

[hkaussie]

I also recommend the Rocks (markets are nice, when they are on), and you can walk across the Harbour Bridge from that area. Taronga Zoo which is world class, Opera House and surrounding area for the view, and the Botanic Gardens, which are wonderful for running around on real grass and picnicking on the grass.

Darling Harbour is ok too though very touristy, and has a couple of good playgrounds. If it's unpleasant weather look into all the museums to see if they have any kids' exhibitions on. The Powerhouse Museum could be a good one to start with: http://play.powerhousemuseum.com/

Have fun.

[cyberfish88]

Thanks for all the good info, especially on car seats LeahH and kiwiinoz. That helps a lot.

How stroller friendly is Sydney, especially the trains? Is it reasonable to think we can get almost anywhere using the train system (even Airport to downtown) with just our Maclaren stroller and a baby bjorn?

[nicolejoy]

Expect to be annoyed by the trains - they're no where near as clean or efficient as Hong Kong!! It depends on where you are going, but if you're going away from the city a bit, sometimes the trains only go every half hour or something crazy - so it's more important to check out timetables!! http://www.cityrail.nsw.gov.au/

They do have a train from the airport to downtown. It's not an "express" one like Hong Kong though - the airport is much closer to downtown but the train still takes probably half an hour (and doesn't leave as frequently either!!)

I've never taken a stroller on the train, but most stations do seem to be pretty accessible for that kinda thing... I DO think that Sydney is MORE stroller-friendly than Hong Kong!!