I'm also an EE, i use 6 x 22" screens in a 3w x 2h setup using a single nvidia card and a pair of matrox triplehead2go units.
I've been using this setup for over a year or so and couldn't imagine doing design work efficiently on anything smaller.
My usual setup is something like:
1 screen with schematic
1 screen with board layout (or firmware IDE)
1 screen with e-mail/IM/etc
1 screen with browser
2 screens with datasheets or extra browsers or terminals
Some times i also need to work with multiple VM's / remote desktop connections and having a full screen for each one is great.
I would like to eventually change to 1 large center screen and rotate the 2 22" screens on the sides of it to a portrait orientation for better datasheet reading but thats not really possible right now under linux with the nvidia + triplehead2go approach
I'm hoping nvidia will put out a similar type of card as the ati linux drivers are pretty meh.
I've messed around with viewing things on all 6 monitors at once, movies/games. Never really liked it. I just need all the space.
Getting more monitors has been the biggest increase in my productivity since i left college, i can see the same being true for anyone doing design work on a computer (CAD, graphics editing, video editing, etc).