I find it offensive: squarely in the baby-poo, vomit, etc category.
Edit: I'm referring to the background of the "alert" bar as well as the "welcome" box for not-logged-in users.
I love the SU Colors.
I see mostly blue.
I like blue.
I think the SuperUser colours are way better than Serverfault or Meta. Ok, Jeff hates Meta, so it gets the ugly scheme. Fine, I can deal with that. But Serverfault... blech. SuperUser has a nice theme IMO.
I like it better than the gray Meta look...
Pretty much duplicate of Thoughts on the new superuser logo and theme?.
To answer your question, I think the colour scheme garish, even hideous.
Looks medieval. Try white on white.
I really don't like the bubbles around the tag names. It makes them stand out too much, IMO.
There is one drawback with a blue scheme. Older people, discriminating myself here by giving a specific age boundry at about 40-45, tend to have difficulties distinguishing different shades of blue.
You probably mean for questions with accepted answer. I find nothing "offensive" about that color.