well there is noting much going on in market so might as well add my 2 cents
cogs you mentioned Riesling - my personal fav a few years back was Jim Barry (Clare Valley) a lovely drop
my all time favourite wineries to visit are Rockford and Grant Burge
Rockford do an amazing Alacante Bouchet, not sure if you can get it at the shops but it is stunning on a warm day or with a spicy dish their basket press full bodied red is sublime to top it off the winery itself is fabulous all looks and is the same as it was 100 years ago - none of these fancy places for me! http://www.rockfordwines.com.au/
That being said my other favourite is Grant Burge they do a whole range and as I have a relative that works there I have regularly been though the list several times! My absolute fav though is the Meshach - I was fortunate to buy a bottle a few years ago - before it got so pricey but for a full bodied red I reckon it is better than Grange. for those that like the bubbles their sparkling the pinot chardonnay is fantastic and makes a regular appearance for special occasions http://www.grantburgewines.com.au/
