Well, think about what the world was like when people fist started doing techno and stuff back in the late 80's

There was no Reason, no Floops, softsynths were unheard of and there were no sequencers with audio capabilities. Add to this trying to sync 808s, 909s and 303s using the DIN sync, which was dodgy most of the time. Add to that maybe a DX7, perhaps a Juno, and maybe some sampler like
AKAI S950. Now think how some great stuff was done using pretty much these basic means of production.
Fast forward to 2006, and well, what you've got is way too many choices, most of which just confuse everybody, make everyone think that they "have" to have some piece of gear because it's the "standard" in some genre of music. Add to this all the unlistenable, washed out, cliched, formulaic stuff that's beeing released and you realise that it's not the tools, it's the person using them.
So, I guess what I'm trying to say is don't worry about what "tools" you need. Just come up with a setup that you feel comfortable with, allows you to create the sounds you want, and is efficient for you. There is no software, hardware, instrument, mixer, soundcard or computer that's specific to a certain genre of music (.... OK, OK a 303 has become the staple sound of acid, but, only in the same sense as guitars are part of heavy metal... you can do other music using either of these instruments).
Having spewed out all that nonsense, probably some kind of an audio/MIDI sequencer/DAW will probably make your life a lot easier than using the sequencer in
the xp50. The big four are Logic, Cubase, Sonar and Digital Performer.
Reason and Floops might be good choices when first starting out, but eventually you will outgrow them.
A couple of other good choices are Traktion and Magix.