I write all my songs in Logic Pro 9 now, but tried out the demo of FL Studio and Love IT... my good friend told me about it when it was Fruity Loops but for whatever reason I didn't adapt until now. Since it's PC only, and I'm just used to mac, I make loops in FL to add to other projects but usually finish a song in Logic.
The only software that I've ever been tempted to leave Logic for is Live. Its great but the feeling didn't last. I have some songs out there in Itunes and Spotify plus other services.
A-Face, "House Of Cards, Falling" out now