Sticking to one set bpm range is really gonna make your style sound stale.
You have to think about the mood of the song, the lyrical content, the message you're trying to get across. Also, if you're chopping samples then there are certain restrictions; timestretching or pitch-shifting too much is just gonna wreck the sound or lose the quality of the original. If you listen to some Kanye, his beats will go from high 60s through to 110, the whole feeling of the drums is gonna be different based on the tempo - he'll pick a bpm based on the sample, artist, market (club, backpack, street) etc.
I'm starting to experiment with tempo tracks in my sequencer (Cubase SX3), and gradually shifting the bpm up or down during the track - faster to increase tension or slower when I pull back and say something deeper. Music made with machines doesn't tend to do that so I think it's a good way to bring a more organic feeling to the music, like not quanitizing your beats to humanize the drums.
Experiment man, thats always the way forward.