One of my main concerns is to minimize the amount of gear it takes to perform. This saves a lot of cost and maintenance, reduces the cables in the signal chain and makes it easier to find and fix problems, reduces setup time and saves cartage which can also save you health problems in the long run. I have used powered JBL EON's for a number of years and found them to be very hardy and clear sounding. The small 10" powered EON's weigh something like 23 pounds each including the built-in digital amp. With the vocal DSP that the PSR2000 has, it seems possible that you could use powered speakers like small EON's without the need for any other mixers/head or outboard gear of any kind.

Also, I think it is important to buy speakers that deliver as flat a frequency response as possible. Keyboards have a very wide range of tones that sound best when all tones are heard evenly. The Peavey speakers I have worked with required extensive amounts of EQ to achieve flat response, whereas JBL's did not.