If you're walking in Vienna's Inner City, and there is a swarm of people around a location, you can play 20 questions with the starter: Museum, Café or Church? I'll be focusing on churches today, as religion has always held a fascination for me personally, and Catholic Churches have the distinction of being some of the most ornate buildings in existence.
1. A priest walks into St. Stephan's and has to pay a 3 euro fee.
Definitely the most, well, let's say titheing of the churches, it seems that you can't walk five feet into St. Stephan's cathedral without paying some type of fee. It's about 4.50 euro to go into the catacombs, another 4.50 to go up the elevator into the tower, 3 euro to see the pulpit up close, and .70 to light a candle for your favorite problem case (light one for me!). There was a minor scandal when, in order to pay for renovations, they allowed advertisments to be projected onto the church. I mean, if they would admit that Calvin was right about the correlation between salvation and earthly success, they wouldn't have to mind so much.
2. A professor of Symbology walks into Peterskirche
Next we have Peterskirche, which is supported by... Opus Dei! Luckily, I didn't see any albino monks named Paul Bettany whipping themselves with a cat o' nines. This church is much smaller than St. Stephan's but makes up for it with free organ concerts and the distinction of being one of the oldest churches in Austria!
3. A nun walks into the Franciscan Church, and then leaves to go to a café
In the Inner City, the Franciscan Church probably should be your third choice (or the Jesuit Church near the Stadtpark). More people go to dine at one of the surrounding cafes than opine in its pews. Try Gasthaus Pöschl nearby or Kleines Cafe for some equally contemplative thinking time.
4. Michaelangelo walks into Karlskirche—and then realizes that painting the Sistine Chapel would have been a lot easier if it, too, had an elevator
Karlskirche isn't technically in the Inner Stadt, but it is only a five minute walk away past some of the most anti-theist buildings ever (mostly art houses). While St. Stephan's has your pocketbook crying, Karlskirche has a 6 euro fee that will allow you to shoot up in a glass elevator to have your own little viewing party only inches away from the ceiling dome frescoes.