What a good thread.....
I've just ordered the first two Tim Powers books you mentioned, plus First Light which I could only get second hand....but cheap

I think it's high time Neil Gaiman put something new out......I loved Anansi Boys and American Gods.
The problem I have is that I read so fast...I need 1000+ page tomes to keep me entertained for more than a few days and there's precious few of those that are any good! I just get fully immersed into a decent plot and almost feel like I've lost a friend when it ends! Big sprawling sci-fi operas work well for me - especially when they are part of trilogies or morogies.
Also, try Neil Stephenson. Some of his stuff is good, some poor. I'd recommend Cryptonomicon and the Baroque Trilogy - although neither are SciFi (like much of his other stuff), I think they're his best books. The Baroque trilogy sounds similar to Tim Powers in that it's historical fiction with a twist.
On Pet Semetary, the second time I read it, i got all the Lovecraftian references and it was a totally different story for me. So - also read Lovecraft too if you haven't already.....