I was trying to think of good sci-fi books to rec to abyssinia4077on her recent post, and took a look at my bookshelves, and realised that I needed some help there myself. My sci-fi collection consists of William Gibson, more William Gibson, Doctor Who, Stargate, Dune (unread), Spider Robinson, a wonderfully trashy book called Pzyche that no one but me has read, as far as I know, and that’s about it. It’s a travesty! I do have more sci-fi books, I’m sure, but they’re at my dad’s and I can’t remember titles. I should be getting them soon, though, along with the enormous bookshelf they're in. *rubs hands gleefully*

So, knowing that there are people out there (*looks hopefully at secretrebel*) who like to recommend books and love sci-fi, and have in fact recommended sci-fi books to me which I’ve stupidly not taken note of (I really need to be holding a pen and paper rather than alcohol when people tell me these things – oh, my lamentable memory) – what’s good? 
 
ETA: Just for clarity, I have read Orson Scott Card, Anne McCaffrey, some Harry Harrison, Jules Verne, H.G. Wells, and a ton of Star Trek novels (How Much For Just The Planet rools) - and yes, I'm an ungrateful cow to ask for recs and then say, "But I've read that!" :-)  (But this is making me think I should re-read Orson Scott Card, because I remember very little about those books.)