After seeing Top Gear do that 24 hour event I'd love to try it.
I think if I was doing it and had to use a diesel, I'd probably use something like a Golf or 306.. Cheap, so I wouldnt care that much about smashing it up..
If I could use any affordable car, probably go for my golf (mk2 8v), a fiesta xr2i, or an E30 325i (for something more roomier).