Lack Of Support I see what you have done, it looks OK, but I have my doubts. A 5' span with NO center supports? I think you will still have a sag/drooping problem. And didn't you mention that the load on this shelf will be about 100lbs? Your back edge will be OK, but the front edge will eventually droop. Before I set up a computer system on the shelf, I would make sure that the shelf would support the load. It's a real great feeling to hear a CRASH in the middle of the night, and then discover that the shelf couldn't handle the load. And it won't do the computer much good either!! Weigh your computer and equipment first. Add about 5 lbs to the total for extra stuff on the shelf (paper work, pens, pencils etc etc). Now go get some bricks and such to equal the weigh you have. Place the weights (bricks) on the shelf about where your computer would sit, and then measure accurately the distance from the front edge of the shelf to the floor. Do this for several days running, a week if you can. This will tell you if you are going to have problems with the shelf drooping.
Thanks Mark, I've actually had my computer set up on the desk for a couple months. No sag, no problems. I've even stood on the desk for short periods to install lights (that's 300 pounds. Yikes!) The standard load with my computer and printer is probably around 20-30 lb's, but my 40 pound boys like to stand on the desk to reach this portion of the layout. New Desk with standard computer load + 12oz. And if it all drops, then I'll have a plausible excuse to get a new Mac Pro.:teeth:
That 12 ounces could be too much in addition to everything else. Better drink it and lighten the desk.