Dave,

From your initial description of needs, particularly styles and voices, I would think you could not go wrong with the Yamaha PSR-S900, or better yet, the Tyros3, if it fits your budget. The operating system is very easy to use, the vast quantity of third party style files is second to none, and the voice quality and selection is superb. All of that, plus USB connection, USB storage, hard drive (T3), and a host of other neat features, IMO, points to Yamaha. However, as was pointed out above, try before you buy, and do some extensive research on each of the features you require.

Good luck on whatever you select,

Gary