Dillinger has some important factors for you to consider and i will make this suggestion, read Canebrake's sticky note on choosing your first 1911. he has put together some really good information that could help you make a better informed dicision on your first 1911.
i haven't personally had a lot to do with the STI pistols, i have heard many glowing reviews from those who have and haven't really heard anything negative about them. many have suggested the RIA brand and i too find it to be a very good choice and had one ordered personally. MetroArms American Classic is another good choice, in your budget of $800, you could also check out the Remington R1, which i have and find it to be a very good pistol and very accurate. Springfield Armory is another good choice and i own one of those too, and have had many of them over the years without any problems. another good choice would be a used Colt. if you happen to find one, it too would be a good one to own.
read the sticky notes and then come back with more details of what you are looking for and we will be glad to help you spend that $800!