First of all I agree with Jason that you could likely give up some fleshing ability if you go with Chiangus. Some friends of ours raise Limousins and Gelbviehs to sell as seedstock. Their daughter also has a handful of Chiangus. When you walk through their cows at the end of winter or when grass is hard to come by the Limmy's and Gelbviehs still look great, but the Chi cows are getting pretty skinny.
Second of all, I disagree with Jason regarding using an Angus bull on Angus cows if you are NOT producing breeding stock. The advantages of hybrid vigor are often the difference in beef production between making and losing money. Studies have proven that hybrid vigor will increase a cow's lifetime productivity by 25% (a good reason for keeping back your best halfblood heifers for replacement heifers), will increase calf weaning performance by 5% and calf yearling performance by an additional 4%. Research has shown that a good crossbreeding program will return well over $100/year over straight breeding. The Gelbvieh association has a nice brochure titled "Smartcross" that outlines good crossbreeding practices. Check it out on their website at <A HREF="http://www.Gelbvieh.org" TARGET="_blank">www.Gelbvieh.org</A>.
Another concern I have with Chiangus is that several of them have a reputation for being high headed and knotheads. If you do go with a Chiangus bull, spend some time in the pen with him to be sure he is gentle.
Actually Gary, your question is a bit open ended. If you are selling feeder calves I would encourage you to cross your Angus cows with a good Continental bull (i.e. Simmental, Gelbvieh, Limousin, Charlais). Angus/Continental feeders often bring a good premium. This same cross will do you well if you feed the calves out and sell as fats or for freezer beef.
A very competitive, but somewhat lucrative market is the club calf business. But, you need to know what you are doing and it may take years to build up a reputation to the point where people will be willing to pay you a good premium for your calves. If you do decide to go that route Chiangus, Maine Anjou, and roan Shorthorn bulls are probably your best bet to increase value. Once again, you really need to know what you are doing to be successful in this game.
Good luck!