Streaming multiple video's to multiple device

I have over 300 movies, 1,000 TV episodes and tons of music on my desktop computer. The computer is on my home network along with 2 iPads, 5 iPods and 4 iPhones. I want to be able to stream different movies, shows or music to these devices. If one of my daughters wants to watch Ancient Aliens on her iPod and my wife wants to watch a movie, it will work. iTunes works, but it has a few "bugs" I don't like. The two biggest problems using iTunes is that it takes about 10 minutes for the iPad to connect over wifi because there is a ton of media in the library. The other thing is that the computer will go to sleep in the middle of a show. I don't want to turn sleep off because I want it to go to sleep if nobody is streaming. I have tried windows media player, but it will only stream 1 thing at a time. I have tried AirPlay, but that program will not play in landscape.

Any ideas of anything that will work for me?

Again, I want to be able to stream multiple media files to multiple idevices at the same time. I also want the computer to sleep when nothing is being streamed. Oh, I almost forgot...... Not too complicated to use.

Thank you