Do I need travel insurance before relocating to the UK?

Hi everyone.

I'm moving to the UK from the US on a Tier 1 visa in 15 days. I do not have a job yet and will be recruiting. I know that I am not entitled to NHS without a job (although it seems the enforcement of this is relatively spotty). Do you think I should get travel insurance before I move? (And is this even an option since technically I am not traveling?)  Or should I get a private policy there? Or do you think if I just keep trying to register at various GPs with my visa and NIN, eventually someone will register me and I'll be fine?

patxie - I thought I had read this before check out thread http://talk.uk-yankee.com/index.php?topic=50250.0
Now I am not sure if things have changed but I am sure someone will come along shortly.