The version of both LotR and the Hobbit that I grew up with don't have any illustrations at all, sadly. But we had a map of Middle Earth, illustrated by John Howes, and small books with Hobbit songs. I spent a lot of time with that map! ;-)

Oh yes, the hardbacks/paperbacks problem. I very rarely buy books at all, I prefer to get them from the library because otherwise I'd be broke in a month! Nowadays when I buy new books it depends on what's available; with some books I'm lucky to get them at all, with others I browse until I find a cover I like. But it's rare to get English hardbacks in bookshops here, and I prefer bookshops to amazon, so most of my English fantasy books are paperback.