I will be in Vienna for 4 nights in July and have compiled activities for 3 days. I would like to hear your inputs, suggestions, and comments whether these are too aggresive/laid back, and whether I missed any must-see's.

Day 1:
Take a sightseeing Tours in the morning, or just hop on a street car around the ring to get familiar with the city.
Visit the Schonburn Palace and Garden (this will probably take me the rest of the day)
I want to catch their daily concert at 8:30pm, so I'm thinking that I should have dinner around the area, and come back for the eve concert.

Day 2
The Hofburg's focusing on The Imperial Apt, The Treasury, and the New Palace
Spanish Riding School Performance
The Belvedere's Palace
Stroll through Grassen and Karnterstrasse

Day 3
Lichtenstein Museum
St Stephen's Cathedral

Thanks everyone!!

St. Stephens should be done at the same time as you stroll the Karnterstraße, since it is in the same area. The Lichtenstein museum is out on the D line.

The Hofburg and Sp Riding School are a pretty good way to take up the better part of a day
I wouldn't also schedule the Belvedere for that day--do your browsing and St Stephen's instead

I would also go to the Schonbrunn in the morning, again, it will be most of the day. I'd come back into town, have lunch or a pastry, maybe for the remainder of the pm do a walking tour or your Kartnerstrasse/St Stephen's stroll
Have dinner in town, go back out for the concert. (or do Schonbrunn tour on a day different from the concert)

Because of the crowds, I also think you should do Schoenbrun first thing in the morning, then go back into town for lunch and tour, returning to Schoenbrun in the evening.

Thanks everyone for the feedback! It looks like I will move some of the activities around per some of your suggestions. Has anyone ever toured Schonburn Palace in the morning? I read in one of the threads here that I should try to do Schonburn Palace later during the day instead of the morning to avoid the crowds of the organized tours. Also, is there any other must see's that I haven't listed here? I might have a half day of no set activities yet, so I was looking at either touring the Chocolate Museum (I think I got this idea from Elaine's file ) -- has anyone ever done this? Is it worth it?

A chocolate museum? I'm in love!

Yeah, I thought it would be a cool place to check out. This is the info that I have: Museum of Chocolate: 23., Willendorfer Gasse 2-8 Open Mon-Thurs 10-3, Guided tours, Mon-Thurs 2pm ... Hmm.. wonder if they have free samples of rich dark chocolates???? yumm

good point about the organized tours, I hadn't considered the timing of those
Whe we went in the morning there was a small number of tourists, but it was early March

Elaine did you get a chance to check out the Chocolate Museum?

I believe that you would find fewer people at Schöobrunn in the afternoon than in the morning. As you mentioned above many bus tours come early in the day.
You could visit in the afternoon, have an evening meal at the restaurant in Schönbrunn ( good food) and then take a walk in the gardens before the concert.
This way you can make the best use of your time and see the gardens without the large crowds of tourists.
visit website- www.schoenbrunn.at for opening times and much more information

Note that a combination ticket for the Hofburg and Schönbrunn is available

Molker thanks for the website and for the tip re: the Schonburn and the Hofburg. I think I am going to purchase the Sisi ticket.