If this is your first real impression of the late great Cream, then this album is a good place to start. You can also start with the one that predates it, though, Fresh Cream. This one might have a few more well-known tracks, but both are excellent. Really all the band's albums (all four major releases) are great, but I don't think I'd recommend Wheels of Fire or Goodbye as albums for Cream beginners.
Newcomers or long-time fans though, maybe it's time you picked up a new copy of this album.
I highly recommend the Deluxe Edition of Disraeli Gears released around 2004. A two-disc set, the first has the original album remastered in stereo including outtakes like “Lawdy Mama,” a version of “Blue Condition” with Clapton on vocals, demos of some tracks and a few other demos that were released later during one of the three's solo careers (Bruce's, I believe).
The second disc contains the album and outtakes in mono, which might not mean much to many but is highly sought after by collectors and stripped down live takes from three different sessions on the BBC. There are also extended liner notes and some great pictures of the band including some good shots of Clapton sporting a ragged afro.
Overall, a reissue worth picking up as I think the outtakes, demos and BBC takes make it worth checking out. Definitely a must have album for any rock and roll enthusiast though in whatever format you find it.