If you fly into Vienna's airport and are staying centrally then forget taxis and walk straight on to the CAT (City-Airport Train) not forgetting to buy a 16 Euro return ticket valid for a month.
The CAT whisks you without stopping, in just 16 minutes to the centre of Vienna. From plane to CAT is just 400 yards and from CAT to Vienna Hilton just 200 yards. So convenient!
Having trekked about 400 miles around Heathrow it shows you why more, smaller airports are the answer rather than bigger airports that you can't get to because of congestion.
Updates
Actually the ordinary railway service from the airport to the same Vienna station is cheaper and often more convenient (you can switch to other services if you're going elsewhere in Vienna) and may be faster (if you've just missed the CAT the next ordinary service will get you to town faster than waiting). The CAT is a typical tourist trap. Yes, the journey only takes 15 minutes, but the ticket costs EUR8 for a single. Take the S7 regional train from the platform opposite the CAT, pay EUR 2,20 for a single and be in the city centre in 24 minutes.
Is this your business?