Re: internal server error after activating bp
Hmm however ‘unlimited’ is somewhat of a misnomer, there isn’t really such a thing!
I’m afraid that google search does not really throw up any particularly good hosts or ones hugely suited to WP/BP
Far more important than unlimited space and bandwidth is a server set up to accommodate WP & BP, that will tend to rule out shared hosting or reseller hosting as you might not be able to configure crucial aspects of the server.
A VPS solution is the best starting point really and even cheap/basic plans should provide enough HD space and bandwidth initially.
I do stress the word ‘Tend’ in the above 
It might be worth looking at the hosts that WP recommend as they are naturally all suited to WP WPMU BP
