Based on the Marvel Previews #19, February for April 2014, I'd say you need to pre-order the following books in order to keep up with Spider-Man.
Core Titles
Amazing Spider-Man #1
Amazing Spider-Man #1, variant blank cover
Amazing Spider-Man #1, variant cover Alex Ross
Amazing Spider-Man #1, variant cover Ed mcGuinness
Amazing Spider-Man #1, variant cover Jerome Opeña
Amazing Spider-Man #1, variant cover Marcos Martin
Amazing Spider-Man #1, variant cover Pop Mhan
Amazing Spider-Man #1, variant cover Skottie Young
Amazing Spider-Man #1, variant sketch cover Alex Ross
Marvel Universe Ultimate Spider-Man #25
Superior Foes Of Spider-Man #12
Superior Spider-Man #31
Superior Spider-Man #31, variant cover Captain America
Superior Spider-Man #31, variant cover Kevin Maguire
Superior Spider-Man Team-Up #12
Ultimate Spider-Man #200, cover A by Mark Bagley
Ultimate Spider-Man #200, cover B by David Marquez
Guest Apps
All-New Ultimates #1
All-New Ultimates #1, variant cover by David Marquez
Deadpool #27
New Warriors #3
Spin-Offs
Deadpool Vs. Carnage #1
Deadpool Vs. Carnage #1, variant cover Marko Djurdjevic
Deadpool Vs. Carnage #2
Reprints
Age Of Ultron Companion TPB
Amazing Spider-Man Epic Collection: Ghosts Of The Past TPB
Amazing Spider-Man: Peter Parker - The One And Only TPB
Cataclysm: The Ultimates' Last Stand HC
Infinity Gauntlet Omnibus HC
Infinity Gauntlet Omnibus HC, variant cover