I have to agree and disagree with Uncle Dave. I bought the Yamaha EMX860ST. At $549 it is a great value. I think it has plenty of headroom and crystal clear response. Plus, it has the additional built-in 200 watt monitor amp. I use it with a pair of Peavey 10 inch cabinets for monitors and a pair of 12 inch Peavey cabinets for mains. Sounds great.
I do agree with U.D. (short for Uncle Dave) that the effects generally are below average. I use the effects on my X1 anyway so I don't really care. I thinking about a digitech S100 for additional effects.
This setup has more than enough power for everything but the very large gigs and you don't need an additional monitor amp. I'm happy.