Unless your speakers are a difficult load or very inefficient, I would go with the Yamaha, given these two choices. If you don't have great speakers now, or are about to buy great speakers, the Rotel would be a total waste of money. Speakers make more difference in sound than anything else except possibly the acoustics of your room, and the particular recording used (i.e., the CD, not the CD player; the DVD, not the DVD player). Better to spend the extra money on better speakers, and only bother with a separate power amplifier if the speakers are too difficult for a receiver to drive them adequately.
People often imagine that if components are placed in more boxes, they must be better. However, the exact same circuits can be placed in one box or many boxes, and if in one box, they can be shielded from each other and save you money because you are only buying one box. Separates give you more boxes, though they need not be better. Usually, however, the best amplifiers are built into separates, but that is not always the case. Also, being the "best" in amplification is often unnecessary, as one may not need much power or the ability to drive low impedance speakers, which brings me back to my first point, if you don't need an expensive amplifier, don't pay for one, unless you have money to burn. In which case, you might want to consider equipment other than what you have mentioned in this thread.
