Help with austalian cellar doors....

Have a look at the Tour Diaries. There is more to come over the next few weeks that will complete the Barossa.

You can also see the previous years Diaries if there is not enough in the 2007 Diaries to keep you happy.

I visited the Barossa for a few days last year.
Here's a brief run down of the cellar doors from your list that I visited.

Penfolds
I know it's an icon of Australian wine but I simply wasn't impressed by the cellar door experience. The staff member who was serving us seemed a lot more into flirting with the European backpackers wearing tight tops at other end of the counter than promoting Penfolds wines to us. He poured a bunch of the lower end wines, provided very little info but when we asked to taste some of the better stuff (e.g. Bin 707), he said he couldn't do that. Maybe you need an appointment to taste the better stuff? I don't know.

Two Hands
Before going there I hadn't tried any of Two Hands wines before. The cellar door is attractive and modern, the staff knowledgeable and helpful, and many of the wines were excellent. Try the garden series (Bella's, Lily's, etc) and the flagships if you can. We didn't need to make an appointment but I believe they offer private tastings by appointment.

Yalumba
For such a large operation I was very impressed with the experience at the cellar door. I had not realized just how many wines Yalumba produced and I was mainly familiar with the lower end ones but after spending about 90 minutes there we tasted through many of them including the higher end reds like The Octavius and The Signature. The staff were great and the grounds are very attractive.

Seppelt
I was there only to try the fortifieds which were very good. The grounds are interesting to look at.

Rockford
Had heard good things about them but when we arrived (no appointment) the tasting room was packed and we didn't have a particularly good time. The wines however were very good as I recall.

Some other ones that aren't on your list but maybe should be are:
Dutschke
Appointments are essential. It doesn't get much more personal than the experience we had at Dutschke. Upon arrival we were greeted by the man himself, Wayne Dutschke, who took us into the barrel shed where we tasted through the range of wines while having an interesting conversation with the winemaker about his style and future plans and so on. Then he took us over to the smaller shed to taste the fortified wines. We really enjoyed Wayne's style, the wines and the hospitality. He mentioned plans to build a new cellar door but I don't know if it's been finished yet.

Rolf Binder
Rolf seemed like an interesting character and his wines are definitely worth trying. We caught him on a busy day and he seemed rushed so I think it would definitely pay to make an appointment.

Jacob's Creek
Worth a look if you have time. Our accomodations were nearby so we made a quick stop at Jacob's Creek on the way home one afternoon.

As Ric suggests, check out his tour diaries. Lots of good info there.

Thanx guys!