Forest, you're in very good hands here. Don't get opinions from anyone at Guitar Center!
I work in similar venues and the there's never been a better selection of small, lightweight gear for high quality sound. The Yamaha's are indestructible, and will serve you well (the 7 year warranty say's a lot). I've used both the DSR and DXR series as mains and or monitors, and they do sound fantastic. They also go incredibly loud, and don't fall apart when you push them. I think both require a little EQ cut in the high frequencies, but just a touch of EQ will soften them up nicely. I favor two way boxes with 15's, but the 10" or 12" models will work very nicely for vocals.
You didn't mention what you use for monitors, but if you ever decide to upgrade your mains these boxes will be awesome monitors. You also didn't mention a replacement mixer, so I'm assuming that will come later when you can afford it. There are a handful of incredible digital boards available today, and they will take your sound to a new level. I've been using the Mackie DL 1608 iPad mixer for 5 years, and it has changed my world as a sound engineer. With this, and a good set of powered speakers, there is no more "rack". Digital processing, 6 monitor mixes, 2 effects with returns, all kinds of EQ, compression, gates - and everything available on every channel. The learning curve is not as steep as you might think. There are several new models available now from Behringer, Soundcraft, QSC and Allen & Heath, that many members here prefer. I personally don't think you can go wrong with any of them.
Lastly I agree with those saying you need a sub. A single powered 15 will do a pretty good job. My JBL 18" PRX sub's sound fantastic, and I can dead-lift them by the handles easily (about 90 lbs I think). I've heard good things about the newer Yamaha DXS sub's, but not good things about the DSR sub's, which is odd because the DSR two-way boxes are their top of the line in this price range. I prefer having a matched system, as they are designed to work together. The internal processing is really good, and you might be surprised at first when you find your main EQ is flat in most rooms, if not all. Good luck with your purchase decision, and be sure to come back here and let us know how it all worked out.
