Ahh, season one... The memories come flooding back... When Channel 4 picked this up in the UK in 1995 I was working as an Auxiliary Nurse (initially part-time, then full-time) in a large accident & emergency hospital. Being based in the operating theatres, wearing the "greens" and being only 18, I'm sure I played out (in my head anyway) the whole ER thing! I certainly hummed the theme tune!
I've not seen much of the recent series, so cannot comment too much on how the show is these days, but Anthony Edwards, George Clooney et-al were top back then! The show seemed so fresh and fast-paced and not at all American (as it wasn't annoying!).
I'm sure I caught elements of Season 2 & 3, but lost interest as my career moved away from nursing. Also, I think ER was on initially at a time when in my late teens, early twenties I was more likely to be down the pub'!
Still, I had to buy Season 1 again and if you have fond memories of 1995 (ish) this series may help drag some out of the old memory banks!