Thank you for your great website, and especially to klayymann for posting the 1980 Casio catalogue - it helped me finally identify the F-200 and go searching for one.
A friend at school in 1980 had one and I always liked the square design with round buttons. 28 years later I now have my own that I wear regularly, in fact I use them all.
I can't really remember my first LCD watch, it was possibly a Casio or a Timex, it would have been around 1980. As I continue to look at pictures here and around the internet some memories might be jogged and I will remember (and will then start searching for one).
The following are the Casios I have that I would consider 'vintage', my main watch for years has been the cheapest water-resistant Casio I could find - right now it's an F-91W.
I went looking for the F-200 and through that learned about the F-100, they have damage but that means I'm happy to use them, I do have to constantly remember not to put my wrist under the tap though
I was cleaning up the C-80 today, there are a couple of keypad buttons not working (Edit: now fixed, I cleaned the contacts under the buttons).
The A153 reminds me a little of my first watch, though it has a chromed plastic case (mine was steel).
I'm not planning a big collection, though I know from other hobbies how things can escalate. Watches I have learned about recently that I might hunt for are the Cosmo Phase and a metal version of the F-200 (QS-24?), though both seem to be expensive.
I jotted down the following from various sources, it might be of use to someone, finding info on battery type took me a while:
Casio F-100 (1977?)
Battery - 393 (SR754W, AG5) 1.55V silver oxide
Casio F-200 (1980)
Battery - 392 (SR41W, AG3) 1.55V silver oxide
Casio C-80 (1980)
Battery - 2 x 391 (LR1120, AG8) 1.55v silver oxide
Casio A153 (1984)
Battery - CR2016 3V lithium
Casio A-200 (1997?)
Battery - CR1216 3V
Edit>> The band on the C-80 looks just like one for an F-200 in the 1980 Casio catalogue, but I'm pretty certain it's a copy. On the reverse it says '805 18mm' and 'Hong Kong'. I've also seen this design band on a Tokai (or 'Tokaj'?) calculator watch too. I'm assuming Casio made their own bands in Japan, I will keep a look out for the correct C-80 one. The band on the F-100 is from a modern F-91W, and the one on the F-200 is a new Casio band with an appropriate design, I don't know which watch it is meant to accompany. *Also trying to call them 'bands' rather than 'straps', I'm not sure it matters but I see 'band' a lot more on the internet.