I like Abba! In my musical history, they stand out as being the first of the "synthesizer-based" groups that I enjoyed. They paved the way for many other groups & their music stands up very well today, as evidenced by the popular musical "Mama Mia!" 
 
I just finished watching the video to "Hovas Vittne" (follow the link at JoeyMuppet's blog site). Even though I couldn't understand the language, it was great! (Where's the Chef when we need him?) 

 The point is that their music is entertaining no matter what the language.