don't worry, I don't read sheet music as well, although I'm heading college specifically to learn that shit! lol.
Anyway, 2 VERY core things you need to think about first.
Are you interested in it because you want to be these composers, or do you really just have that burning desire to create similiar music inspired by those composers?
Profession or hobby?
Either way;
Your best bet would definitely be like a Korg Triton Studio or Extreme, depending on your usage for the number of keys. I would go for a Korg over a Yamaha Motif anytime, although overtime you'd be adding other sound modules to your arsenal.
There are a number of multitracking recording programs, like Nuendo, Cubase, Logic Pro, Pro Tools.
You're going to be mixing everything on your computer for starters budget. If you can, get one of the better workhorse stations, Pentium 4, 2G ram, or AMD (any of the later models), 2G ram, or if you're fucking rich, go for a Mac G5.
Next, you'll need a professional audio soundcard. No, not creative soundblaster. That's consumer level. Something like M-audio, Echo, Terratec, RME. You could get that from Team108 Audio or Sinamex. The soundcard is for reduced latency as well as you can play alot more tracks in your software simultaneously in general.
If you do not have money to get a pair of cheap monitor speakers, you can in fact actually use a decent consumer pair you have. Just make sure to turn off ALL enhancements; like mega bass, equalizers, etc. Your speakers have to sound as neutral and plain as possible. Of course different speakers have their own characteristics and all that crap, but eventually you'll have to start producing stuff no matter how. So just live with what you have for now and start working.
If you find that you're more towards a profession;
Now since u're just starting off, I must warn you; many people when they first get into this, they eventually turn into studio-gear enthusiasts. In other words, they spend alot of time checking out, debating, discussing, and lusting for studio equipment. But they don't really churn out anything much music-wise. There's nothing wrong with being an enthusiast for sure, but if you're not rich, this is one REALLY expensive hobby.
If you concentrate on the music you'd love to make instead of often OVER-gazing at other established composers' studios and the latest products, you'll never get anywhere. That's a very very common trend I see everywhere, specially in Singapore.
Now, if you just wanna be like those composers, being drawn rather to a tradition and fame than doing music regardless whatever for yourself, chances are it might eventually turn out into a gear hobby. If that's so....
Enjoy the wonderful world of the studio! It is indeed very fascinating. I'm an avid gear-luster myself, although at the end of the day I pull myself back down to earth again to work on my chops.
Good luck!!
Teo
::Audivarius Studio::