My advice is to stay clear of the Roland Groove crap. A more sensible option would be to invest in a sampler and maybe try out some dance music construction kit cds. If you get a decent PC, you can work with audio files on that.

There are all kinds of grooveboxes out there today. Some are better than the average Roland box, but I'd still go for a sampler. It's so much more flexible and you're not limited to one sound-set. Check out the Akai MPC series. It's a good sampler combined with a table-top like box with pads.

Yes, you can use a groovebox with a PC and a keyboard.

-tek