Probably any of the top three arrangers (Tyros2, G70/E80 and PA1XPro) would make a very decent sound. as good as most any 'keyboard band'. Especially if you make the most of the Yamaha's and Korg's samplers, the sky's the limit.

BUT......... probably the limiting factor is the originality of the styles - there's something about original music that is just...... original! Most of the styles in an arranger are there to imitate stuff already recorded, you rarely get a moment of discovery, it's more 'Oh, this kinda sounds like THIS'

I often use an arranger though to flesh out the initial stages of a song, and then go through all the machine parts and replace them with my own stuff, and use some loops and custom rhythms to make the drums more original (and it is virtually impossible to get any arranger to sound as good as BFD or DFH2 software drum modules!)