Russellc:
Drum Machine:
MPC 2000,3000,xl (pick one)
with a drum machine you can sample as well, also create drum patterns, but in no way or form can you play a melody, well you can, but like chords or 4-6 simultaneous sounds at once NOPE, also you have a sequencer within it to keep your beats tight and percise
Keyboard/sampler: to many to name
with a keyboard you can sample and play keys as well giving you more of a melody with your songs kind of like Eminems part on "Forgot about Dre" you can play that melody, also you have 16 track sequencer
Eight Tracks: ADAT, DA88 ,
MX2424
Personally you should stick with an ADAT, they are more compatable, (meaning) just about anywere you go someone will have an ADAT as supposed to
the DA88. Therefore you could bring tracks from you house all on the ADAT and add, mix,or remix at someone elses studio.
Also if you are intending on copying beats already in the module, then your are by far KIDDING yourself at becoming a producer by any standards, also if you are sampling grooves as you say --- still your hindering your ability to stifle yourself, never advancing to actually see what you are capable of at creating. Sure as you can sample someone else can sample the same exact thing. but to chop it up, or create a new diagram of the song, contributes to being a producer.
hope that helps