The above post was very accurate.
The main talking points have been covered.
You have a fair budget for a projector/screen setup, but you will need to decide how serious you want to do this.
By this I mean, there are some concerns I would have with a front projection setup that I would strongly encourage you to consider:
1. 20 bucks of paint will be the most significant performance enhancement you can make! Forget what you think you have for light control. As long as you have a huge white REFLECTIVE white ceiling, you don't have light control. Instead, look through some magazines at rooms painted darker. You can keep some color, just bring the room down a good bit, especially the ceiling! All the cool kids have painted ceilings these days.
2. Your credenza doesn't have to be at the front of the room. All those blinking lights right in front of your face while you are trying to watch a movie? I would think they are already distracting at night, but in a front projection setup it will be far more of a distraction.
3. A fixed screen gives the best results for the least amount of money, but a tab-tensioned electric screen is a good way to go and allows you to keep the other screen in place. Seymour AV has acoustically transparent tensioned screens for around $2,000 which I would recommend you consider. This may help considering your speakers being so close together and the higher credenza with a speaker sitting on it.
4. The JVC RS45 will give you the best 2D image under $3,500. The Epson 5010 will give the best 3D under $3,500.
5. Overhead is typically the best location for a projector. All the vents are on the sides, so noise comes out the front/sides/back the most, while no noise is directed downwards. So, put a projector overhead and reduce your noise from that projector!
6. All projectors are like PC monitors. They don't have TV tuners or internet functionality. So, you use a Roku player, or Blu-ray or something else to get content to it through an A/V receiver. You are all set for all of that so don't sweat it.
7. Get light blocking celular blinds for your windows and leave the curtains. It will give you solid results during the daytime.
8. You have a solid budget, but not enough to do a proper anamorphic setup, so you should stick with a 16:9 (1.78:1) screen setup. At 14' viewing, a 120" diagonal is very realistic for being the 'proper' size.