Firstly, a little information on what exactly the Hugos and Nebulas are, courtesy of our friend Wikipedia... (I know, but... just read, it'll be okay):
"The Hugo Awards are a set of awards given annually for the best science fiction or fantasy works and achievements of the previous year. The awards are named after Hugo Gernsback, the founder of the pioneering science fiction magazine Amazing Stories, and were officially named the Science Fiction Achievement Awards until 1992. Organized and overseen by the World Science Fiction Society, the awards are given each year at the annualWorld Science Fiction Convention as the central focus of the event. They were first given in 1953, at the 11th World Science Fiction Convention, and have been awarded every year since 1955." [excerpted from Wikipedia] Nominees are usually announced in March / April. Awards are handed out at the World Science Fiction Convention each year in August / September.
"The Nebula Awards annually recognize the best works of science fiction or fantasy published in the U.S. during the previous year. The awards are organized and awarded by the Science Fiction and Fantasy Writers of America (SFWA), a nonprofit association of professional science fiction and fantasy writers." [excerpted from Wikipedia] Nominees are usually announced in February. Awards are handed out each year at the Nebula Weekend Conference in May.AbeBooks has a great list of all the previous winners here, including the 19 titles/authors that won both awards (which might be a good place to start, if you're considering a Hugo/Nebula collection):
- Dune by Frank Herbert
- The Left Hand of Darkness by Ursula K. Le Guin
- Ringworld by Larry Niven
- The Gods Themselves by Isaac Asimov
- Rendezvous With Rama by Arthur C. Clarke
- The Dispossessed by Ursula K. Le Guin
- The Forever War by Joe Haldeman
- Gateway by Frederik Pohl
- Dreamsnake by Vonda N. McIntyre
- The Fountains of Paradise by Arthur C. Clarke
- Startide Rising by David Brin
- Neuromancer by William Gibson
- Ender’s Game by Orson Scott Card
- Speaker for the Dead by Orson Scott Card
- Doomsday Book by Connie Willis
- Forever Peace by Joe Haldeman
- American Gods by Neil Gaiman
- Paladin of Souls by Lois McMaster Bujold
- The Yiddish Policemen’s Union by Michael Chabon
And to give you an idea about collectibility: if, say, you're lucky enough to own a first printing of Ender's Game by Orson Scott Card (Tor, 1985), then you may just have a collectible worth $500 to $2,500 (assuming it's in Fine condition). If you have a first edition (even a later printing) of Frank Herbert's Dune (Chilton, 1965), you may have a collectible valued anywhere from $400 (in Good condition) to $15,000 (signed, in Fine condition) - seriously.
Those Sci-Fi nerds aren't so nerdy now, are they?