One of my favorite albums that always sounds (excuse the intended pun) fresh every time I listen to it is Fresh by Sly & The Family Stone. The feel and groove of the music is so loose, yet still so tight at the same time. The lyrics are amazingly clever and strong too. I even sat one day and wrote them all down in a notebook. They are actually already written in the artwork, but I still wanted to write them, almost like I was taking dictation. Let Me Have It All is one of the sickest vocal performances.The Chili Peppers did a pretty cool version of If You Want Me To Stay which is on the album.
It is the most played album on my iPod no doubt. Here is the website to check it out, and lots of other info on Sly: SlyStoneMusic.com