As my DAW, I use Cubase 5. As a composer more than a performer, I generally use vst instruments more than actual instruments. I hook up my keyboard and electronic drum set to my computer, and record with midi (which works fine as you can get them to sound really close to real instruments, but sadly they'll never be as good as the real thing). For my drums, I use Superior Drummer 2, and hook my Alesis DM6 electronic set to it. For piano, I hook my keyboard up to a vst called The Grand by Steinberg. I usually end up recording the bass guitar, and get someone else to record the guitar and I put them through a plugin called guitar rig 4 (sometimes, if I feel like cheating, I'll use realStrat to generate a clean guitar synth, but only for solo guitar). For orchestral stuff, I use Eastwest Quantum Leap Gold. For my synths, I usually use Massive.
As far as audio effects go, I just end up using whatever is built into Cubase that sounds good. No special plugins there other than my amp simulator =P
I'd give superior Drummer a 10/10 hands down. It is, in my opinion, the best drum vst out there. It sounds flawless. I usually end up putting the bass and snare drum through a compressor though.
The Grand is very nice for playing softly. When you wanna play faster, more upbeat things, however, it ends up sounding a bit robotic and MIDI, even after messing with the expression and effects.
Guitar rig 4 is beautiful. Nuff said.
EWQL Gold is a very nice program. Messing around with the expression and vibrato makes the instruments sound incredibly legit and beautiful. Very great for a full, powerful orchestra. I'm looking at getting Albion by Spitfire though, as I've heard nothing but good things about it. Although from what I hear, EWQL is better for the full orchestra, but the individual solo instruments sound better on Albion.
RealStrat is nice. It's about as good as guitar synths go... which isn't very good xD Guitars are next to impossible to make convincing with midi instruments. Although, when using the right effects in Guitar Rig, I can usually make a relitively convincing solo guitar. Rhythm guitar is out of the question though =S
Massive is pretty nice, but I haven't played around with it that much yet. I rarely use synths in the music I make.