When I (and David, I guess) was growing up in (then) Rhodesia, the penny had a hole in the middle. We used to collect a "penny string" which was obviously a stack of pennies on a string. When you got to 240 of them, you hopped on your bicycle and went to town to a bank to get a one pound note in exchange for about 3 lbs of coins. This was a LOT of money even when I was a teenager. 240 US cents or even 240 new pence is chump change today.
Thanks Clive, the old system was even more complicated than I thought!
By the way, the speed of light can be expressed as 1.8026*10^12 furlongs per fortnight.
Thankfully there are no British units for electricity & magnetism :)
I liked the old system -- much more fun. Especially the difference between a pound (20 shillings) and the guinea or sovereign (21 shillings). The difference came about because the value of the paper pound floated with respect to the gold sovereign. They finally standardized the sovereign to 21 shillings.
The one pound coin is an interesting animal. It's a fairly small brass-colored coin, but very thick so rather heavy. This makes it easy to distinguish from all the other coins, but it does "tend to make holes in one's pockets".
The one pound coin came out when Margaret Thatcher was Prime Minister. The new coin was called "The Maggie" because it's "hard, brassy, and thinks it's a sovereign".
So when is the USA finally going to come up with a successful dollar coin? My opinion: at the very least they need one on which George Washington looks exactly like he does on the one-dollar bill. It would also help to have it gray on the front and green on the back.