in terms of region it would be very obviously the wineries in Lower Austria, and more specific Wachau,Kamptal,Kremstal and Weinviertel (which means literally "wine quarter

)
In terms of grapes Grüner Veltliner (GV) is the most typical austrian wine since it fits the region best. There are excellent Rieslings but i would rate them below the best german ones.
Since around early 2000 a region control seal modeled after the french AOC has been introduced: the DAC
within this system there is the further distinction of "Klassik" and beyond that the "Reserve" wines. Reserve has even stricter rules
In the Wachau they have introduced a quality system themselves before that using names "Steinfeder", "Federspiel" and "Smaragd"
So the usual top wines from the regions today are usually "winery X DAC Reserve Smaragd" Sometiems extended with the usual "Alte Reben" (="old vines") or "ÖTW" ("austrian traditional winery") or "erste lage"/"1.lage" ("first terroir"). Or sometimes all three of them
Prices for those obviously can be through the roof (20-30+ euros around here for a DAC reserve smaragd) especially if supplies dwindle of past years since those stronger white wines are usually even better after 1-3 years. After all they have around 13,5 -14% alcohol. Can be dangerous drinking them on a sunny afternoon
Buying a great DAC Reserve from the "non-Smaragd" regions in lower austria can be just as good. And is usually cheaper since many customers are crazy about that Smaragd "branding" (DAC reserve i would say around 12-19 euro).
I have yet to drink a "average" DAC Reserve (Smaragd). On that level the austrian wineries are usual top notch and absolute safe bets.
Doesn't make the normal DAC wines or even non DAC wines from the region bad though: the lighter DAC (12-12,5%) can be good value (7-10euro, sometimes even less) for excellent wines.
Sometimes a non-DAC/not-yet-DAC can also be good but that's up for the personal tasting. I also bought two bottles of a rather heavy (13%) non-DAC in addition to the DAC Reserves which i found great but 5 bucks cheaper.
If you prefer very fruity,sweeter,younger wines compared to the dry/massive/fresh/pepper GV another grape which i find personally excellent and typical for austria is the Gelber Muskateller(Muscat Blanc à Petits Grains).
Really underrated and doesn't get reviewed feverishly. This grape single handely converted me to a wine drinker.
Because it's really,really fruity and more sweet than usual it is also betterfor drinking "Weiß-Sauer" (White-sour) which is an austrian summer classic: white wine with mineral water.
Usually the cheaper Welschriesling wines are used for that (they can be much cheaper) but those have more acid, and less taste.
Discovery of the season for me: Gelber Muskateller Frizzante. Holy smoking Jesus. A wine lemonade with 11,5% alcohol. A must-try
Best regions here are in Burgenland around the Neusiedler see andin styria because the increased acid balances the wine better. Lower austria is perhaps sweeter.
Welschriesling is a tough call: there can be great ones for 15 but it's also the really really cheap 2 wine. Because of that it's difficult to find a great one.
Poured in the glass they can smell fantastic with incredible bouqet but after one sip you often realize that "it's all show" because they taste very light.
Can be drank in big quantities because of that. I'm not a fan.