Hi, I was using FL for the same reason you do, you can use the piano roll to edit sounds and it is incredible to modify the length of the notes, but Cubase also does it but it's not quite simple as FL, for example In Cubase it's very dificult to control the WAV files, Kicks, Snares, All wav files, but I found a VSTI that makes magic, "KONTAKT" (thanks stalker BTW ) he recommend me that VSTI you just have to get to know with the program . Cubase It's more powerful then FL. well it is just a sugestion.
you also can try Ableton Live. I think you won't find any secuencer easier than FL.