After a lot of dithering and coming up with reasons not to I have finally deactivated both my Twitter and Facebook accounts. I don't use them and just can't see myself doing so any time soon.
I had previously deleted accounts on a number of services that I had joined over the years so these were the last holdouts.
Do I worry about someone taking my name in future when it can be recycled? No. This blog and my primary email accounts (.me.uk and .blog) are the canonical representation of me on the internet and I don't need anything else.
It's been a long time coming and I'm happy that I finally summoned the mettle to do it.