iRealb is my favorite. Honestly, this has been my single most valuable tool during practice time for the last year. I use it all the time. Thousands of free charts are available on their forums, and its easy to make your own charts. Independent volume sliders for drums, bass, guitar/piano are great. rhythm style and tempo can be adjusted for all tunes. You can repeat certain measures over and over.
*Drum machine - Pick a tune, pick the style (bossa, straight ahead, straight 8ths, rock, etc), drop out everything but the drums, set repeats to 12, shed.
*Play Along - Pick a tune, pick a style, drop out the bass, shed.
*Songwriting - Amazing song editor allows you to make chord charts and jam with your song. It has a fairly useable roadmap tools allowing repeats, bridges, codas, ect. Also you can save as pdf and send to your band.
Sadowsky Vintage Jazz V
Mesa Boogie Walkabout