I had a fairly detailed one with the big caveat that it was a plan and plans change. Long and detailed didn't mean inflexible, it meant that if everything was proceeding normally I didn't want to be answering questions and if if wasn't they had some idea of what my wishes were.
It was a wish list essentially and I got most if it. So stones we had to compromise - I had the choice of wireless CFM or a midwife preent the whole time so I chose CFM.
I had good reasons for a lot of my choices which were, and still are, painful to talk about and certainly not something I was going to dredge up during labour. My birth plan was there in part to explain those and the possible ramifications as well as the ontingencies agreed by my obstetrician and MW. My first question to any new caregiver was 'have you read my birthplan?'. It avoided a lot of unnecessary chatter.
So if you're the kind of person who would rather be left alone then a detailed birth plan is well worth it and stick to your guns about MWs reading it. I think it saved me making choices in labour because I'd already made them with as many contingencies as possible.
From memory mine had 3 sections:
Labouring environment - private, quiet, no hospital gown, knock before entering, minimal MW presence, free to move
Pain relief and intervention - minimal possible, G&A or pethidine, no epidural (I preferred GA and signed a waiver saying I understood the risks), tear rather than episiotomy, CS preferable to ventouse or forceps but if absolutely necessary GA or sedative before ventouse/forceps
After birth - immediate skin/skin with me or DH, let cord stop pulsing before cutting, baby to breast immediately, prefer to find put sex for myself, no injection, cleaning/weighing to wait, yes to vitamin K, no other treatment unless indicated, cotton wool/muslin and water only fir cleaning baby, one of us to stay with him at all times