Sci Fi/Fantasy is by far my favorite genre to read. However, I find myself in the middle of like five different series right now and I feel like it's a bit much. Everything I'm reading so far I like, but it's the constant rush of having to pick up the latest in the series that sometimes puts me off. Does anyone have an suggestions for one shot Sci Fi/Fantasy novels that would fit the bill. Authors and and series that I like are: Jim Butcher (both Dresden and Codex), Mercedes Lackey (working my way slowly through Velgarth) , Trudi Canavan (both Magicians Guild and Age of Five), F. Paul Wilson (specifically Repairman Jack) and Douglas Adams. Any help would truly be appreciated. Thanks in advance.

Might I suggest some books by Tim Powers?  Most of his books are standalone.  On Stranger Tides, and Anubis Gates are two of my favorite books.

I'd also suggest Good Omens by Terry Pratchett & Neil Gaiman -- a very humurous take on the end of days.

Thanks for the first two recs. I've never even heard of them.  I've read Good Omens, which made me laugh alot. Big fan of all Neil Gaiman's books as well.

Brandon Sanderson did a standalone called "Elantris" that I found very entertaining.

What about Tad Williams "The War of the Flowers"  or JV Jones "The Barbed Coil" ?   I  read and enjoyed both of those. Also Judith Tarr has written some good stand alone fantasy novels although I can't think of titles off hand.  Happy hunting!

Sunshine by Robin McKinley.  Wonderful urban fantasy.

A Fistful of Sky by Nina K Hoffman

The City, Not Long After by Pat Murphy

Michael Stackpole has some stand alone fantasy books:

Once a Hero [best book by him in my opinion]

Eyes of Silver

Dark Glory War [technically a prequel to a series, but it can be read as a standalone, and the third best book by Stackpole :-)]

Talion: Revenant [2nd best book :-) ]

Practice Effect is a transfer to another dimension where the rules of improving items are different.  You make things very crudely and then the more you use them the better they get.  It splits the difference between Sci fi and Fantasy. 

I also liked Mathemagics by Margaret Ball.  It's a Chicks in Chain Mail book about a single Mom from a dimension where magic is performed with mathmatics trying to make a living and raising a teenage girl in suberbia but the bad guys from home won't let her.  It's fun and an easy read.

Thanks for all the recs all. I've added many of them to my wish list. :)

Check out Mercedes Lackey's retelling of beauty and the beast if you haven't already, it's called Fire Rose.  Also, The Magicians by Lev Grossman.  It's really dark but I think it's kind of intresting if you like psychology.

Larry Niven's Footfall - Alien Invasion against modern day Earth.  Aliens gain the upper hand but Humans find a way to win.

L. Ron Hubbard's Battlefield Earth - Alien Invasion, Earth loses and then several generations later, a leader figures out how to take Earth back.  The movie was VERY Loosely based on the book and only told half of the story.

I would suggest The Dispossed by Ursula LeGuin for sci-fi, it is an older book but makes you think about societies and how they do or don't work.  For fantasy, Guy Gavriel Kay has several, Tigana and Lions of Al Rassan are my favorites of his.

Not a stand alone but if you like Mercedes Lackey you might really enjoy Tamora Pierce.

Neil Gaiman's Neverwhere is excellent.

Patricia Wrede's Sorcery and Cecelia, or the Enchanted Chocolate Pot is excellent, and can be read as a stand alone, even though there are 2 sequels.

Claire Dunkle's The Hollow Kingdom is good, there are 2 other books but I didn't think they were as good as the first, and the first can stand by itself.

The Sherwood Ring is really good-Elizabeth Pope.  (and it is a stand alone)

Edited to add-Diana Wynne Jones is fantastic-there is a thread down below about her passing-Howl's Moving Castle is good, and was made into an animated movie.