Based on the Marvel Previews #103, March for May 2012, I'd say you need to pre-order the following books in order to keep up with Spider-Man.
Core Titles
Amazing Spider-Man #685
Amazing Spider-Man #685, variant cover Gabriele Dell'Otto
Amazing Spider-Man #686
Amazing Spider-Man #686, variant cover Gabriele Dell'Otto
Amazing Spider-Man Annual #39
Amazing Spider-Man: Ends Of The Earth #1
Avenging Spider-Man #7
Scarlet Spider #5
Ultimate Spider-Man #10
Ultimate Spider-Man Adventures #2
Guest Apps
Avengers Vs. X-Men #3
Avengers Vs. X-Men #3, variant cover J. Scott Campbell
Avengers Vs. X-Men #4
Avengers Vs. X-Men #4, variant cover Mark Bagley
AVX: VS #2
AVX: VS #2, Fight Poster variant
X-Men #28
X-Men #29
Spin-Offs
Venom #17
Venom #18
Reprints
Amazing Spider-Man: Parallel Lives
Amazing Spider-Man: Secret Origins TPB
Marvel Masterworks: The Amazing Spider-Man Vol. 7 TPB
Marvel Masterworks: The Amazing Spider-Man Vol. 7 TPB, variant edition
Marvel Universe Spider-Man: Amazing Fantasy Digest TPB
Spider-Man: Big Time Ultimate Collection TPB
Spider-Man: Identity Crisis (new printing) TPB
Ultimate Comics Spider-Man: Death Of Spider-Man Fallout TPB