We have a hardback of the Beatrix Potter tales, which DD loved being read for years. She's now 8.5.
I treated myself to a hardback Narnia compilation a few years back (I had the full set in soft covers and different versions so not matching - but DSis had ruined a couple and DBro lost one, so I had never taken them from home). DD is starting to read that now.
The Richard Scarry books are great. We had a few over the years at home, which DF had brought back from his travels to the US and UK, including a big hard back one which my DBro had (and when the leaves came apart after a couple of years hard use, all 6 of us used to slide down the stairs on different pages!!). But they were still very readable. DD has a softback compilation of 3 and loves it.
Dr Suess are also great, have different levels as the DCs develop and some are hard backed/hard board pages for younger readers.
The Book People also do Mr Men and Little Miss collections cheap(ish) at times. We got a box set of Roald Dahl books from the Book People when DD was about 2-3. We read lots of those aloud for years at bedtime (we're currently down to 2 nights reading per week (from all 7 up to last year) and on 5th Harry Potter book, she has loved chapter books for years) - and she has just started "The Giraffe, the Pelly and Me" in reading group in school! Lots of RD have been re-read umpteen times (and were well loved favourites of DH and I also).
Santa is bringing DD a box set of 3 HB Harry Potter companion books this year (rules of quidditch, a Hogwarts textbook and a book by Dumbledore??).
DD loved the Naughtiest Girl series by Enid Blyton (even dressed up as Elizabeth Allen for World Book Day in school in Senior infants - to the hilarity of the teachers given DD's propensity to be quite like EA in chaos-causing but generally well meaning as a result of aspergers/ADHD which had just recently been diagnosed at the time). She also likes the Secret 7, and Famous Five, and wants to start both Malory Towers and St Clare's series, but had no time for the Magic Faraway Tree, Noddy, or Mrs Tiggywinkles and other EB's aimed at very young children.
Also if you are thinking of Christmas books, there are plenty of lovely ones that would last for years. I know we have a collection of Mr Men seasonal ones, one with a bell (about a cat chasing mice), Tiger in the Snow, "24 Petits souris" (the daily adventures all through December of 24 child mice, their parents and grandparents preparing for Christmas - it's in French), the Polar Express, and a couple of Usbourne stories and others, filling 1 magazine rack that comes out in December. I keep "Twas the Night Before Christmas" with the Christmas decorations, as I don't read that until Christmas Eve every year (the others are all through December) - all those get put away in mid January.