Putting everything on raid0 is imho not the best practice, because it does not give you any redundancy. If any single drive in a stripe is lost, all data on that raid0-stripe are lost too. So I'd recommend to use at least raid5, or raid10 (if you can waste some disk-space). If all your drives are equal, you could put one or two aside as global hot-spares, and use all others for a few raid5 spans.
If your apps are i/o sensitive, you should use some kind of serious caching (~1GB cache on raid-controller is not enough). I think Dell uses re-branded LSI-controllers, so something like LSI CacheCade might come handy (caching on ssd). One more nice feature is "hybrid raid1", that is raid1-mirror with ssd+hdd supported by some controllers: ssd is used for i/o, and hdd is slowly synchronised in the background. Of course, it depends on your budget...
