i use reason (not as much as i should) and it's a great startin point plus there's alot of stuff you can do with (specially now with the combinator) but i would stress definitely get something like fruity loops/cubase/acid as well cause you can use vst's with reason
also the effects in reason aint great but again you can make em better with the combinattor (i am still to really use this myself)
i know somebody who used to write tracks dry in reason and them export the individual tracks out into another sequncer so he could use vst effects and write other parts with vsts synths etc
i am trying to learn fruity atm but i am not a massive fan of it atm but that's prob just cause i dont get enough time to sit and use (i'm usually practicing my scrathing on the decks )
I'm a fruityloops strictly kind of boy. as a drawback it is very different (easier to use imo) from cubase and reason, but you can do all the same things with FL than most popular sequencers. Sometimes i do that dry/semi-dry mix out of fruity and do the rest (mixdown and mastering) in another sequencer.
Other than that, not much to give info on except to listen to lot of music and start collecting samples from where ever you can get them.
Learn as much as you can about the physics of sound. I can't stress this enough. If you don't learn this then you'll just end up writing average tunes (maybe not musically, but as far as clarity goes).
And practice!! you can't get good overnight, it requires years of hard work, similar to learning an instrument, although it's like learning 5 million different instruments. Read mags like Sound on sound and computer music, sometimes you gotta sift through some crap but there is some gems in these mags.