The key to good balance is in the recipe. Too much malt, and too little hops, means a too-sweet beer. Too many "body building" ingredients will cause a "thick" beer.
Mash temps are also very important. If you want a thinner bodied beer, you can mash at 149 or 150 to have more simple (shorter chained) sugars while for a thicker mouthfeel and more body, you can mash at 158.
For example, my cream ale is low on IBUs, mashed cooler than an APA, and uses corn to lighten the body. It's thin, dry, and crisp. My oatmeal stout is loaded with flaked body, crystal malt, etc, and mashed at 156 or 158. It's rich and full bodied.
Both have an OG of about 1.050!