Penny,
The different kinds of roti are as diverse as the regions that the people who eat them inhabit! There is really thin roti (called handkerchief roti), and there is some roti you "smash" up so it looks like ribbons (my favourite!), then there are more flat-bread style ones similar to the Greek style flatbread. This brings me to the regionality of cooking in general: I think its true that many diverse sets of people use a flatbread to eat with. I can think of this being used in India, Pakistan, the Caribbean, Greece, and the Middle-East. I worked at an Italian pizza place once, and we made a kind of flatbread with just plain pizza crusts for cheese platters.
In the Indo-Caribbean culture I grew up in, we use roti in place of cutlery for some meals. Typically there are several different kinds of food cooked in sauce and one takes some of each, gets some roti and devours.
I almost forgot to mention
Dosa from the South of India!! That's a totally different recipe, but ends up being a food that I would call roti style.
I'm a chef by trade, and food is a passion, hope that my reply was inspiring (and not overwhelming),
If you've yet to try eating with roti I suggest you give it a try. Be warned, some styles are greasy....but use your judgement!
Happy eating,
Amjad