Global pass or select pass? Or individual country passes?

Before you buy a Global Pass, shelling out $1300, consider using a combination or regional day tickets, advance purchase tickets, a bus or two. That can cut your transport cost by 50% or more.
Regional day tickets in Germany will cover all the local transit until 3 am the next day.

Zürich is good for bankers, but not a touristy city. Spend the time in Luzern (aka Lucerne) instead.

All the cities you listed have one-day or longer passes which include all local transport, tram, bus U-Bahn and S-Bahn.

I would advise you to price up the trips individually, using the DB (German railways) and SBB (Swiss Federal Railways) websites, http://sbb.ch and http://bahn.de
A bit of homework required, but I think you will find this cheaper than passes.
For longer trips, if it is an IC or ICE train, you need to book and reserve in advance (2-3 months) to get cheap tickets. For local trains (R, RE, IRE, S-Bahn), there is no advance purchase discount and no reservations the price is the same if you buy on the day.

There are various local passes available, for example the Länder tickets valid for a day for one German Land (=state), which are great value. Lots of postings on this site about them.

If you take a train from Zürich to Vienna, it goes via Salzburg, and it is a long train journey. Consider visiting Salzburg as an overnight stop between Luzern/Zürich and Vienna, instead of as a day trip from Munich.
Another option is Frankfurt - Zürich/Luzern - Munich - Salzburg - Vienna - Prague.

Rail passes do not cover in-city transportation, except for S-Bahn in most Germany cities (not buses or U-Bahn). In Switzerland, passes also cover the lake boats, on the same days that you count for train travel, and give you discounts of about 25% on mountain lifts. Guidebooks will summarize the best local transport tickets in each city.

You can't buy a pass more than 6 months before you'll start using it. If you are traveling in 4 countries, then the Select pass currently fits that region and offers 8 days of train travel within 2 months for $567 per person in 1st class (or $434 per person in 2nd class if you're both under 26 when you start the trip). To compare more pass prices in a side-by-side table format, see http://www.ricksteves.com/publications/rail-guide-form, but note that prices are subject to change at any time (and are currently lower than the examples in that PDF). For the routes you've mentioned, seat reservation fees are optional, not required, which means the pass gives you a lot of hop-on convenience and flexibility.

(This only pertains if you are using US dollars) With the US dollar growing stronger each day against the Euro, a global or select rail pass purchased in US dollars would be throwing your US dollars away. I would definitely purchase advance point-to-point tickets in euro (not US dollars) through the diverse train web sites or else wait until I got to Europe and purchase my point-to-point tickets there. Europe is fast becoming a bargain especially in the years ahead as the US dollar gains significant strength against the Euro and Swiss Franc.

Wow, that stronger dollar sounds awesome! Of course, if the dollar gets stronger, the price of a rail pass will be adjusted downward accordingly, as already happened a few times this year.

Before you think about buying any rail pass, read this, from the rail guru The Man In Seat 61: http://tinyurl.com/bkw4u6c

You will most likely do MUCH better buying individual tickets for your train travel between countries, and local transit passes for your transit within each city. Mass transit in European cities is generally inexpensive.