Something I've always admired in an artist is the ability to use words that I did not previously know. If I require the use of the dictionary to find the meaning of the word, then that artist has done a good job. This does not mean that the song is incomprehensible. It simply means that one word in that song was previously unknown to me. I appreciate that song all the more because I had to work to get something out of it. Here's a few artists that have used big words well:
Natasha Bedingfield- "Unwritten"
Relient K- "Up and Up"
Jordan Anderson- "Stand Up"
Black Eyed Peas used a big word, but it didn't really make that much of an impact.
There have prbably been a few others that used big words, but I don't remember who they are.

The always lovely Natasha Bedingfield