Here are a few of my tips:
D’Arenberg’s cube finally opened last December. I haven’t been inside yet but everyones talking about it. There’s a restaurant, tasting room, museuem among other activities. Might be worth a visit.
I’m suprised nobody’s mentioned Yangarra. Wonderful wines, especially if you’re interested in Grenache and Rhone varities, and great cellar door.
The view from Samuel’s Gorge is WONDERFUL, and the wines are nice and the staff friendly and unpretentious.
In the Adelaide Hills, I’d reccommend Tappanappa (Brian Croser). Tiers Chard comes from what I think is the oldest commercial vineyard in the Adelaide Hills. Their Pinot is also very good. Also, I’d second Deviation Road, not only for their sparkling but for their Pinot Noir as well.
For something different, check out Handorf Hill winery. They were the first to grow Gruner Veltliner in South Australia, and are making some really interesting wines from it now. The Blaufrankish is pretty good too
If you’re interested in some of the more new wave/alternative/“natural” Australian wines, particularly from the Adelaide hills, the Summertown Aristologist has fantastic food and a really great collection of small producer, natural wines…however, buyer beware! Alternatively, just visit any wine bar in Adelaide.
The Crafters Hotel has a back room with a lot of old European vintages. I think they have rooms also. They’re really close to the freeway and easy to get around to other wineries in the Adelaide hills. As for Clare, I think Mintaro is bit of a drive from most of other wineries (and civilization), but it depends on the experience you’re looking for.