the keyboards/Modules are all on you, you have to decide which sounds best for you. there really isn't a need for a drum machine if you have a keyboard.
But for getting audio and MIDI in and out of your computer, you are goin' to need a MIDI interface and an Audio Interface. These days quite a few Audio/MIDI interfaces have been comin' out.
Same thing with the Programs. The graphical User Interface(GUI) Is all merely personal Preference. I can do the same tasks with Cubase SL as I can with Pro Tools. Most DAW's(digital Audio Workstations) generally do the same things. It's all a matter of what works best for you, what isn't goin' to slow down your workflow, if something slows down your workflow, then the idead you have in your head cold be gone before you get to it.
I'll reccomend Cubase SX or SL, they work on both PC and Mac Platforms.
The Digi 002 or Digi 002 Rackmount versions are both reall good deals. you get a high quality audio and MIDi interface, as well as the software, which is pretty much the new standard these days. Reason is a great program as well, but you can't record audio in it, you need to feed the audio into another Program to record it.
Here's a list of some of the gear I have:
MAC G4 Tower Dual 1.42 Ghz Processor, I gig of Ram, and a 120 GB Hard Drivewith a Mac Studio Display(17" Flatscreen)
MOTU 828 Firewire Audio Interface(MOTU Just came out with An 828 MKII, which has both MIDI and Audio Ports for a decent price, motu makes great products)
MOTU Midi Express XT MIDI interface(8 ins and 8 outs, plus other like being able to play live keyboards without using the computer)
Korg Trinity Workstation
Korg MS2000R Analog Modeling Synth
E-MU Proteus 1000 with the Pure Phatt expansion Board
I have a Cheap Behringer Mixer for now, the mackie boards are hella bank. It doesn't matter anyways, I dont record from the Behringer, Only for monitoring or really, really rough mixes.
ART Pro MPA Tube Mice Pre
DBX 166A Compressor/Limiter
Event PS6 Studio Monitors
AKG C3000B Condenser Mic
Mackie UAD-1 Powered plug-ins PCI card(Can't use this until they update it for MAC OSX.
Banshee talkbox
Cubase SL
Toast Titanium
Plugsounds Drums & percussion elements(Virtual Instrument Plug-in) I was really digiin' this plug-in when I was workin' on OS9, it's supposed to be updated for OSX in July.
Antares Tube Plug-in(I really like this pug-in, it has areally nice sound to it, from sutble to obvious, good Plug-in for the price it's at)
One more thing you should not skimp on if you're looking for quality, is the cable. I just recently swooped some monster cables, and I noticed a huge difference.
Off to the side I still have my old iMAC with all my old beats/Projects/Porno. I'mm keepin the porn off my new computer.
I just listed all my gear, maybe that would be a start for you, search online at some Recording Magazine sites, check out some reviews on some products. Or just sart picking up magazines like Electronic Musician, Home recordiing, recording, EQ. Always Research the gear you want to buy, before purchasing, I've made bad choices in tha pst, and you can never trust most the employees at Guitar Center. They will just sit you in front of any gear and try to sell it to you.
Or they claim that parts work for this paricular piece of gear when they aren't even compatible. Check out some manufacturers sites
www.us.steinberg.net
www.digidesign.com
www.motu.com
www.emu.com (they have samples of their sound modules at work, I really like the sound of their products)
www.korg.com
www.uaudio.com.
If you have any other questions feel free to ask.