I'm not a Deadhead, never have been, but for many years I lived among folks that were pretty obsessive about the Grateful Dead and got to see something of the subculture that surrounded the band. I guess you could say they were precursors of the "slacker" generation, just living till the next time the band rolled through town (and you could be sure they would) or packing up and driving however many hundred miles to see a show. There used to be a pizza restaurant in my hometown that had literally thousands of bootlegs of Dead shows in cabinets behind the counter; you could walk in, name a gig you'd been to seven years earlier, and they'd have that show on tape. We're talking SERIOUS obsession.
But when you listen to the studio albums, the one thing that strikes you is how laid-back they all were. The songs meander, they tend to shift in and out of focus (probably not surprising given the heroic drug intake). But they're great songs! Which is why I've tended to go for cover versions rather than the original. One of the best to my mind is this Warren Zevon/David Lindley version of one of their most famous songs. It's got a proper driving rhythm, it's focused, the musicianship is sharp and clear. "Trouble with you is the trouble with me/Got two good eyes but we still don't see/Come round the bend, you know it's the end/The fireman screams and the engine just gleams." A good song for driving.