My approach to is similar to Tim's.

The idea for a song can come from any number of stimuli,a popular catch phrase,items in the news or either unusual or very typical situations we can identify with.
Humor and irony are favorite approaches when writing.

The melody and style is usually lyric driven, trying to match the beat to the lyrics in a style that fits the subject.
Some of my best work in this part of the process occurs in the middle of the night, trying to get back to sleep.
Always keep a pen and paper handy by the bedside.

And don't forget the creative energy and acoustic properties of the long,hot shower.

Most of the time I can figure out the chords on my guitar. If not I go to my keyboard.

Here's another approach I'm trying on my latest effort:
Band in a Box: Entering Notes using Computer Keyboard and then adjusting them in the Notation Wndow

https://www.youtube.com/user/xyz4469?feature=mhee#p/u/12/HSYfMieyzAo

Once I have the basic chords down in BIAB it's over to Realband to finish it up.

I guess my question as a relative newbee is: What are the advantages of finishing the song in Reaper, Sonar or some other DAW.
Is the end result really worth the learning curve?

Thanks Mitch for starting this thread.

Carkins