I have noticed that throughout Germany, most of their major landmarks are constantly under rennovation or restoration. This is obviously a long term good solution, but I do feel a little slighted on my trip there, because most of the things we saw had tarps around them!
I guess that just makes for a good excuse to go back!!
As of August 2006, the whole city center around 'Rathausplatz' resembles a huge construction site, as they build what they call the 'new center' / 'Neue Mitte'. This has been going on for 3 years now and will go on for the next few, though they already accomplished much. So is the Ulmer Muenster cathedral which you won't see without scaffolding for the next 100 yrs probably. But don't worry, there are many other places to enjoy.