When I think Hip-Hop, I think, "this person doesn't know how to play any musical instruments". I know this isn't necessarily true but that's how I think since Hip Hop is dominated by loop based music and "djs" which are not to be confused with musicians.
There are many DAW's that are good for looping. Abelton's Live!, Sony Acid, Fruity Loops. Really any DAW will do. Most offer looping capabilities. What you might want to consider though is what type of interface are you using? If you don't have a recording interface, when you buy one, you are likely to get some sort of software with it.
Since we are talking about Hip Hop, you likely only need one input so that narrows down your choices. PreSonus products ship with Cubase LE or Cubase AI 4. Mackie products ship with Tracktion. And of course Digidesign products ship with Pro Tools LE.
There are so many options it's hard to say whether there is a best or not. Download Acid Express and try that out.
Try the Fruity Loops Demo. That's got a great engine for beat generation.
Here's the Ableton Live! Demo.
Honestly. Just pick one. There is no "best".