Thanks for all the posts here! I checked the forums in planning our 13 days in OZ and wanted to return the favor by posting a few notes, but don't have the time for a full trip report:
1. Sydney - lovely meal at Wine Odyssey Australia in the Rocks section, great service, interesting food, not cheap but good value; the Taronga Zoo and Botanic Gardens not to be missed for first-timers; Bondi to Coogee walk was fun - about 2-2.5 hours with stops for photos, food (bring a swim suit and towel to enjoy the water if you have the time, and there is some snorkeling, including a scuba trail at one of the beaches), buses from/to Circular Quay were frequent and reliable
2. Blue Mountains - we spent two days and would have spent more, they were awesome; went on the Valley of the Waters walk with head guide Tim Tranter of Treadlightly Ecotours, about four hours and Tim was magnificent, there wasn't a question about the flora, fauna, archeological/cultural/geological and even political history of the area that he couldn't answer. Highly recommended!
3. Canberra - interesting insight into the creation of a modern capital city, the War Memorial was fascinating for those interested with the advantage that if you stay around until after dark, there are kangaroos that come out in the park behind the Memorial. The rabbits don't wait until after dark! The relatively new (2001) National Museum gave useful and fun background on the development of the country and on aboriginal culture. We enjoyed it, but Canberra is not an essential for a short visit to OZ.

4. Tasmania, Tasmania, Tasmania - we only had 6 days, could have spent a month. Hobart's cute (Maldini Restaurant on the Salamanca stretch was very good), but the island's convict sites and the parks and scenery were the big deal. Port Arthur, Maria Island, the Cradle Mountain Park (with a stop at the picturesque town of Ross en route) were all unforgettable. We thought we had missed our opportunity to go to Maria Island, because we weren't going to be there in time for the 9:30 a.m. ferry, but we stopped at the information centre anyway on our way to second-choice Freycinet to see what info they had about the area, and lo and behold, the company that does 'round the island cruise tours had room to take us over at 10:30 a.m. when they left to pick up tour participants from the island! So we dashed to the IGA to pick up provisions for the day (no food to purchase on the island) and grabbed the chance. On the ferry back at 4 pm, someone asked if they could swing by the Painted Cliffs, and they did. Camping there, with bikes (can be rented), looked VERY attractive. Ross, small town on the Heritage Highway between Hobart and Launceston - some convict labor history, the Wool Centre has interesting display of various types of raw wools and information about wool processing, and their shop has good sweaters and other woolen goods. A shop next door has nice wood products. Nice place to stop and lunch.

5. Cradle Mountain National Park - I know, it's Tasmania, but it's worth a separate number. For us US city folk, Cradle Mountain was a delight -- we arrived late afternoon at Cradle Mountain Lodge and when we got to our cabin - there was a mama wallaby with joey in pouch right next to the cabin! We went straight to the Tasmanian Devil center for an evening exhibition - very worthwhile, instructive and fun. Next day, stopped in the park's information centre and got the ranger's advice about walks. We used the park shuttle buses and found them frequent and convenient, though they do get full and reach capacity mid-afternoon, at least during the summer. (The driver recommended getting on in the wrong direction if need be during heavy periods)
We started at Ronny Creek, and hiked 3 hours, ending up at Dove Lake. The Marion Lookout link described on maps as "rough and steep" is, but if you are reasonably healthy and willing and wearing proper shoes, it's doable even for us 60-70 y.o. seniors. That afternoon, we did a shorter, boggier (read: WET) hike - the Seeler Creek circuit. Birds. Wallabies, even a couple of kangaroos. More birds. More marsupials. Gorgeous views (we had crystal blue skies, no rain...and they get 200 rainy days a year, we were told, so YMMV!)
Walking stick note: A walking stick was very welcome in Blue Mountains - only one, a second would have been in the way - but at Cradle Mountain, a stick would have been a nuisance off the wooden paths -- it was too boggy in most areas, and on the steep scree-y parts, hand-holds were more important, and dangling stick would have been in the way.
Now, I'm ready to go back and explore the northwest and northeast of TAS and the rest of OZ...