Cheers!
Kronnenhalle is also worth a stop as is the Widder bar.
I really like Rivington & Son's . They do seasonal cocktails. There's a small team of bartenders and every month or so they meet up with their suggested cocktails for the season. They will then vote and pick the ones that get into the cocktail menu. It's limited, fresh and new. It's not a well stocked out bar like the Old Crow (which has an AMAZING whisky selection).
I've also tried Raygrodski . It's great to see a female bartender (finally) in Zürich. The drinks are not quite to my personal taste but I know many who love it. It has some pomp and more effort in presentation than the others and the ambience is hip.
Dante is a gin bar with some selection. It's busy on weekends when standing room may be difficult to find.
Hope this helps. Finally the cocktail scene is trickling into Zurich. I'm also happy to hear about more bars. Just for reference, my cocktails are Old Fashions, Rob Roys, Clover Clubs and I love experimental stuffs that are balanced, which is why I like Rivington's.
Old Crow is the best when it comes to classics (sometimes with a twist) and if you're a whisky fan, that's where you want to be.
Old Crow is the best place in ZH for classic cocktails. Their execution is consistently flawless, the service impeccable, the presentation and decor a bit more understated. Run by great people who appreciate a discerning customer. They're not especially experimental. Their spirits selection is massive , currently around 1050 bottles. Of all the places listed, this is the only one I've gone to so regularly that the entire staff knows me by name, for what it's worth.
Raygrodski does more avant-garde stuff, in a super-hipster environment.
I'm surprised nobody has mentioned Clouds (Prime Tower). It does great drinks with an unmatched view. The bar side is more mixology, while the bistro serves some tiki drinks. The downside is that it can be rather popular, so especially on the bar side, it can take a while for drinks to arrive. (But they're so good...)
Widder Bar makes great drinks, including some more experimental things. But I find the atmosphere rather pompous and oppressive.
Onyx (the bar at the Park Hyatt hotel) makes great drinks. Just ignore the older gentlemen with paid company...
Dante has a nice selection, but I've found the cocktails to be inconsistent. But the primary reason I hardly ever go there is how incredibly crowded it gets on weekend nights.
And for a less cripplingly expensive night out than the places above, I highly recommend Barfly`z (Yes, that's the spelling and punctuation, sigh...). While their execution isn't quite as good on some drinks, their selection (something like 200 drinks on the menu) and average price of only about 13 francs makes it another favorite amongst my friends.
Another place of note is Central , located at Helvetiaplatz right next to Xenix. They focus on a small selection of classics. When I was there, they had barrel-aged Americano or Manhattan, IIRC.
I've found the Clouds bar to be inconsistent but you're right, they do do some good experiments. I had something in the skull there once which was smoked with fennel tea.
I do prefer the bistro atmosphere (view more towards the HB and Höngg) and the cocktails are decent and if you have a favourite, they sometimes get the guy at the bar to make it.
Thing is Rivington's does more interesting stuffs IMHO and located just at the bottom of the same tower.
They're near Selnau station and Stauffacher tram stop.
4Tiere is cool as well, specially for me because I love gin.
Some other noteworthy ones :
Felix near Kalkbreite Tram Stop.
Bar Münster in Neiderdorf
Brick near Helvetiaplatz