What are your most-reread books?

[lproven]

I've been trying to think what I have reread the most times.

I am not 100% sure -- I don't keep records -- but it's probably something like (& I'm bundling sequels in here):

[1] The Hitch-hiker's Guide to the Galaxy, Douglas Adams
[2] The Dark Side of the Sun, Terry Pratchett
[3] Strata, Pratchett
[4] The Colour of Magic, Pratchett
[5] Red / Green / Blue Mars, Kim Stanley Robinson (would be higher but for their length)
[6] Chaga, Ian McDonald
[7] Good Omens, Neil Gaiman & Pratchett
[8] Blood Sucking Fiends, Christopher Moore
[9] Riotous Assembly, Tom Sharpe
[10] Zen and the Art of Motorcycle Maintenance, Robert Pirsig