Ortho at Lowe's: Dial'N Spray Hose End Sprayer
Try this link to see a picture of a hose end sprayer. You screw it on to the end of a garden hose, fill the small tank with whatever you need to spray, dial in the concentration on the sprayer, point and squeeze the trigger. It can cover a large area in a small amount of time.
I have about 350 plants and have used these sprayers for fertilizers and insecticides. For me, they are more then twice as fast as the pump sprayers and put out alot of mixture to really douse my plants. I also don't have to reload them as much as the pump sprayers.
On the minus side, the hose end sprayers cover a wide swath and are not nearly as "strategic" as the pump sprayers can be. This isn't usually a very big concern for me as my grow area is outside and fairly open - although I usually do manage to spray our sliding glass doors with the hose end spayers.
When feeding, I use the hose end sprayer during our dry season as it waters and fertilizes at the same time and I use the pump sprayers during the rainy season when the plants need the food more then the water.
For pesticides, the pump works great for small jobs, the hose end for covering large ones.
Seems to work well so far.