I love the music apps. My top 5 would have to be:
Ocarina
Ocarina is the first true musical instrument created for the iPhone. Both experts and beginners will be amazed by this innovative player. Ocarina is sensitive to your breath, touch and movements, making it even more versatile than the original. Unlike other musical applications, there are no pre-compiled riffs so musicians will find unlimited opportunities for self-expression. Advanced options allow you to choose between diatonic, minor and harmonic scales.
GrooveMaker
GrooveMaker allows anyone to create and share non-stop tracks for remixing, multimedia and movie soundtrack compositions on the go, in real-time, just like a professional DJ or music producer. GrooveMaker has quickly become the top downloaded remixing applications for the iPhone/iPod Touch with nearly 500,000 downloads, allowing any user to create professional, full-length tracks in minutes, with its unique combination of advanced remixing software and high-quality included loops' sound content.
PocketGuitar
PocketGuitar turns your iPhone or iPod touch into a virtual guitar. You can press and strum strings, just like a real guitar.
You can choose the sound from 6 instruments ? Acoustic-Electric Guitar, Electric Guitar, Classical Guitar, Muted Guitar, Electric Bass and Ukulele. You can also choose effects from Distortion, Chorus and Delay and edit parameters.
FourTrack
FourTrack multitrack audio recorder is a songwriting and practice tool for singers, guitar players, piano players, and others who want to capture musical ideas and record songs on the iPhone and iPod touch.
Drummer Tracks
Drummer Tracks are backing tracks of JUST DRUM GROOVES that range from 2-5 minutes long (song length) and include the natural variation of live drums played by the pros! They are ideal to jam along with, practice or use to write or perform your own music. The starting points can be any kind of style, including the styles of classic drummers and bands complete with recreated sounds of the album and more. It's all available to create your own sound with and to play along to with authentic human feel, dynamics and realism. It's like soloing the drum track out of your favorite recordings and YOU being in the band! Drummer Tracks are fun and made to be the easiest way to get into the sound of top quality sampled drum sounds from Sonic Reality.