For sampling and sample recording I use Ableton Live. The program comes with a nice suite of software and addons to help make beats, extra sounds etc. It is multithreaded so it can take full advantage of your multi-core system (if you have one). You can record multiple inputs at once and layering is really easy. The interface is not conventional (most multitracking software has everything laid out top to bottom) so if you're used to that at all it can take a small amount of time to get used to it. There are plenty of tutorials on youtube however which help immensely in figuring out what everything does. It does come with a decent price tag but as with most software, the more you use the more you get out of it.