Should I but a sightseeing pass, museum card, or cumulative ticket for Venice?

Sightseeing passes, museum cards, cumulative tickets, and other discounts in Venice

There are several cumulative ticket museum passes and discounts for pre-booking. Here's my evaluation of the relative usefulness of each, with prices from 2013:

• Museum Pass ★★ (covering 11 civic museums and sights)
• Chorus Pass ★ (covering 15 major churches)
• Venezia Unica (a pre-booking service for sights and services offering minor discounts)

Museum Pass ★★

A single ticket that costs €24.50 (€18.50 for students under 29; families of two adults and at last one child can get one pass at full price and the rest at the reduced price) is valid for six months, and good for entry to each of the following 11 municipal museums (www.visitmuve.it — to book it: www.selectitaly.com):

• The four Museums of Piazza San Marco—Palazzo Ducale (Doge's Palace), Museo Civico Correr, Museo Archeologico Nazionale, and Sale Monumentali della Biblioteca Nazionale Marciana. [These four are otherwise all covered by a single admission ticket, called the I Musei di Piazza San Marco, that costs €16.50].
• Ca' Rezzonico (museum of the 18th century; €8.50)
• Ca’ Pesaro (museums of modern and Asian art; €10.50)
• Museo del Vetro (Glass Museum on Murano; €8.50)
• Museo del Merletto (Lace Museum on Burano; €5.50)
• Casa di Carlo Goldoni (author's home; €5.50)
• Museo di Palazzo Mocenigo (costume museum; €8.50)
• Museo di Storia Naturale (natural history musem; €8.50)

Coverage: Covers one can't-miss sight (Doge's Palace) and three excellent secondary sights (Ca' Rezzonico, Ca' Pesaro, and the Museo Correr). The others, frankly, are more of specialized interest, or if you happen to be right there and have some extra time (though if you plan to go to Murano or Burano, those two indigenous craft museums are worthwhile).

Savings: If you use it to visit just the Palazzo Ducale plus any one significant non-Piazza San Marco sight (such as the Ca' Rezzonico or Ca’ Pesaro) and you've at least broken even if not alrady saved money. After that, everything else on the list is, essentially, free. It also lets you skip any ticketing lines, which is nice.

Should I get the Venice Museum Pass?: If you plan to do a lot of sightseeing and are staying for two or more days, get the pass.
Note: If you use the official ticket-booking site for Venice civic museums (www.vivaticket.it), don;t let it steer you toward to much, much more expensive "MUVE Friend Card" annual membership (which costs €45). You can still buy the regular Museum Pass there, in person at a museum, or ahead of time at www.selectitaly.com.
Book it: Select Italy.

Chorus Pass ★

Venice was the first city in Italy to come up with the ignominious practice of charging people to visit God. Sixteen of its major churches—with the notable expectation of the biggest and best, the Basilica of St. Mark's—banded together to charge admission.
Individual entry into any one of the member churches costs €3.
The Chorus Pass granting entry to all 16 costs €12 for individuals, €8 for students up to age 29, or €20 for a Family Pass good for two adults and any kids up to age 18. It's good for one year.
Coverage: Fifteen churches scattered across town—including such biggies as I Frari (full name: Basilica of Santa Maria Gloriosa dei Frari ) and Il Redentore (Chiesa del Santissimo Redentore)—as well as Santa Maria del Giglio, Santo Stefano, Santa Maria Formosa, Santa Maria dei Miracoli, San Giovanni Elemosinario, San Polo, San Giacomo dall'Orio, San Stae, Sant'Alvise, San Pietro di Castello, Santa Maria del Rosario (Gesuati), San Sebastiano, and San Giobbe.
Savings: Visit at least four member churches, and the pass has paid for itself. Any others you pop into from then on are free.
Should I get the Venice Chorus Pass for churches?: In town for more than three or four days and gung-ho for a lot of sightseeing? Go ahead and get the pass.
Book it: www.chorusvenezia.org

Venezia Unica

Venice used to have something called the Venice Card (rip-off), which became Venice Connected in 2009 (still pretty worthless), which became Venezia Unica in 2013 and is still not really worthwhile—especially since it adds a €5 to €20 fee on top of the total (the amount varies dpeending on what services you sign up for—you get to pick which items you want on the card).
What it boils down to is this: book ahead of time (unfortunately, a whopping 15 days ahead of time), and you can shave a few euro each off parking, municipal WiFi (€5 per day rather than €8; or €20 per week), and a daily (€3 for two "visits") or weekly (€9 for once visit daily) pass to use the public toilets.
(The very fact that Venice charges you for public toilets is insulting and inhuman—and a reflection of how hard the city actually tries, in very subtle ways, to keep the hordes of tourists away by making a visit vaguely uncomfortable and unpleasant on many levels.)
Sadly, It no longer even offers any additional discount on vaporetto passes or the airport ferry—and the discount on the Museum Pass is a pathetic €0.50.
It does, however, get you a dicount off if you buy a "pack" of musuem and church passes:

• €24.90 for a "San Marco Pack" (covering the Msuei di San Marco and your choice of 3 churches; retail that would be €25.50). Savings: €0.60.
• €39.90 for the full "Adult Pack" (all Musuem Pass sights plus all 15 churches; that would retail for €36.50). Savings: €3.40.

Coverage: Modest discounts for the full sightseeing package, parking at the main garage on Piazzale Roma, municipal toilets, WiFi access. Savings: It saves €2.60 off the parking garage, €0.50 to €3.40 on sightseeing, €3 off WiFi, and €0.50 off the use of the public toilets. Whoop-dee-doo. Should I get the Venezia Unica card?: No. Not now that is doesn't help with the most useful and expensive items. (Don't) book it: www.veneziaunica.it