By far the coolest work benches I've ever had are sections of bowling lane. Normally, if you can find a bowling alley being dismantled, someone will claim the lanes, then cut them down into about 10' chunks and sell them. I had three in my last shop, so 30' of bench space. Normally they are too wide, so I ripped about 4" off a side and turned it 90 degrees and used it as a back splash. Keep in mind that there are about a zillion nails holding each lane together and you'll go through lots of blades ripping them.
Another thing to keep in mind is that they're heavy. Each section probably weighs about 250 lbs, so it takes 4 strong men and a boy to mess with them.
Surprisingly another problem is that they will sag (across the width) if you don't support them. I used 1" angle iron screwed into the bottom about every 3 feet or so for extra support.
I use sections of 3/4" galvanized pipe for the legs.
Finally, they normally come out of the alley with the sides unfinished, so you need to trim them out.
They take a fair amount of effort to set up, but once you're done, they will make all your buddies drool.
I just moved from our old place and am just building my new shop, so they're sitting on the ground right now. When they're back up in place, I'll post some pictures.
As others have said, lots of outlets are great. Water on a garage type reel is nice. I've also plumbed air all over the place, both along the walls in in drops from the ceiling. In my last shop, I used copper water line for air, but I've used schedule 40 PVC and it works great as well.
I also use a fairly light grey paint on the floor. It makes it easy to clean, plus dramatically increases the reflective light when you're working on your back. The fancy epoxy stuff is nicer, but way expensive.
Dont' forget the fridge painted and made to look like your snap on tool box. Neighbors like that.
Impossible to have too much light. I had several 8' flourescents, plus several warehouse lights up high.
Although it doesn't look as neat as running everything in the walls, I ran everthing, air, power, water, etc outside sheetrock where I can get to it. Makes it so much easier to add things or deal with problems.
I also made curtains out of fairly thick plastic, so that when they drop down, they give me about an 8' by 10' paint spray booth. Just roll them up and tie them to the ceiling when not in use.
Big box fan mounted on the floor, blowing out through some grating I put in the wall. That way when I'm done welding or painting, I can get the air exchanged quicker. Also helps with cooling in the summer.
I've also got a piece of flexible metal dryer vent type stuff which vents to the outdoors. The other end slips over the exhaust of whatever equipment I happen to be working on to help the atmosphere in the shop. Use it for everything except race bikes we have.
Can't have too many small, kitchen fire extinguishers hanging on the walls.
Also can't have too many things that lift stuff. We have air operated table lifts for motorcycles, but we use them for everything, mowers, implements etc etc. I also wouldn't be without our old forklift. You can buy them cheap and they're great to have in the shop for all sorts of stuff. We have an old Hyster 3 wheel model that I think I paid about 1,000 for and its made life way easier.
I also plumbed in a wash tub type sink, that just drains into a dry well out back and hooked up one of those instant hot water deals. Has saved me countless whippings from a ticked off wife for messing up the kitchen sink.
I love building a new shop.
