Songs with solid lyrical content, preferably using a large vocabulary and utilizing lots of allusions, similies, and metaphors. Doing so without using profanity is good and easily done. Doing so without profanity or made up words for forced rhymes (mo, flo, ho, etc.) is even better.
Lots of punk and metal fall into this category, from what I have seen. Its easier for me to sing along with classic rock and country, though.
Lots of classical music is ... soothing, for lack of a better word.
Favorite bands, in no particular order, would be:
Rush
Manowar
Dropkick Murphys
Jethro Tull
The Offspring
Iron Maiden
:cheers: