Growing up with sci fi in the eighties and nineties I adored the work of Edmund Cooper, but he doesn't really get too much recognition. I suppose writes such as Clarke, Asimov, Niven and Pournelle overshadowed him. His stories were similar in tone, but I thoroughly enjoyed them anyway. My favourites being A Far Sunset, The Cloud Walker and Seahorse in the Sky. His novels were also my first introduction to the artwork of Christ Foss.
Tie in books don't seem to get the recognition that they deserve, either. Some of the Star Trek books were superb. Star Wars less so, but still very enjoyable. Warhammer 40, 000 is brilliant. (Especially the Gaunt's Ghosts.)
May favourite book after all of these years remains Iain M. Banks's The Player of Games. I was fortunate enough to get a hardback of it a couple of weeks ago. I've read it maybe nine or ten times now, but I haven't reread it for a while. Maybe I should.