Having been across most of the UK, I can safely say that londons public transport is easily the best (kind of out of necessity as it's nigh impossible to get anywhere on time with a car, considering the amount of traffic).
That being said however, it's not like other cities fall far behind. The UK has really good bus & train networks outside of london, and given that other cities have FAR less traffic, the buses are actually usable.
Most stuff has already been said, but I'll just add my 2 cents:
I/O is very important. I got a laptop with a pathetic amount of ports and I deeply regret it. Don't be like me