Yes I have, some years back I created a few instrumentals/beats and tried rapping on them. I sounded horrible. lol. I'm not good at singing but i'd say i'm pretty good with making beats. I still occasionally put together a few instrumentals but I stopped using Fl Studio ever since i switched to linux, am currently using LMMS, Its an open source alternative to Fl Studio. I'd highly recommend it.
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.