Mulitchannel music creation program with samples

Question

I want to create songs with melodies. As I don't have a band at hand I need to synthesize the instruments (I'll record the singing).

So, I need a program that

• Has multiple channels where I can add the tracs for the various instruments (at least 8, but 16 or more would be better)
• Sample capabilities for instruments I don't have (at least piano, drum, violin, trumpet)
• Runs on my Linux machine native, offline.
• Must have a gratis trial version if its software I need to pay for.
• Must have a nice GUI.
• I'll pay for it, if need be.

Ideally it also

• Has a wave sampler (for more "techno" sounds)
• comes with a rich set of precreated, commercially usable sound samples.
• Is Open Source Software
• Is Gratis
• Has a Windows Counterpart for other members of my band that do not run linux, but I will convince them if its good.

Answer 1

I suggest taking a look at LMMS:

• Has multiple channels Yep 64 of them
• Sample capabilities for instruments I don't have (at least piano, drum, violin, trumpet) Cello, Organs, pianos, flute, harpsichord, guitars, trumpet & violins & lots of drums.
• Runs on my Linux machine native, offline - Yes
• Must have a gratis trial version if its software I need to pay for. It is just gratis
• Must have a nice GUI. Some think so, others will disagree.
• Has a wave sampler (for more "techno" sounds) lots & lots of effects
• comes with a rich set of precreated, commercially usable sound samples Yes
• Is Open Source Software Yes
• Is Gratis Yes
• Has a Windows Counterpart for other members of my band that do not run linux, but I will convince them if its good. Linux, Windows & OS-X versions 32 & 64 bit
• Lots More