ok so i am primarily a guitarist. i have been using garageband for some time and as a solo musician i am getting increasingly frustrated. what i really need is some software for mac that allows me to preprogramme a complete backing track (bass, drums, synths etc) for a song easily, preferably with the same sort interface as is used with drum machine software, ie put a blip where you want the drum or note to be.
it must allow me to be creative with it in any time signature i want, being able to change tempos midway through the song would be great, must include good and natural sounding instruments and allow me to sample my own sounds for use. if anyone knows of a good bit of software like this please let me know, il be very grateful.

im tired of the endless recording sessions that hardly get anywhere and the never ending production and overanalyzing of every single sound. i want something quick and easy for making great demo's that i can basically record along with while singing and playing guitar so it is more like a performance than weeks of frustrating work.
logic is so expensive tho :-(