Hey Sven.
We'll see what the client says
About the software, I've used ModPlug Tracker for some game-music; it's free and you can "borrow" the sounds from other modules that you can download hundreds of.
However, it doesn't feature very many effects/the alike, and is sort of poor if you compare it to todays official music-making software (obviously, since theese costs quite some money).
For myself, I'm currently using Kontakt 2 with some extra sound and effect packs; it's best for making orchestral music, even though it's of course possible to write rock/etc (alas, you'll have to buy some add-ons for the right guitar sounds).
There aren't a lot of ambience-sounding instruments included either, but you can get hold of quite a few here and there.
Then there is GigaStudio, which is told to be the best out there; I haven't been able to afford it though and seeing as it's obviously "made for a mac-environment", I haven't really paid any big attention to it either.
Anyways; ModPlug is free; Kontakt 2 is not cheap, but it's definitively one of the best PC samplers around.
(As for the note-inputting; I'm using Sibelius in cojunction with Kontakt 2 for that).
"I kören hörs de brummande busarna Björnligan och Gondolen"