For the first four of the five parameters you mention (and probably for most other parameters, too), I think it’s going to be pretty hard to do better than [I]Interactive Brokers (UK)[/I].
(Their customer service has improved a lot over the last year or so, but I think it’s probably still fair to say that they expect customers more or less to know what they’re doing, and they don’t like to do a [I]lot[/I] of “hand-holding”, overall. Of course, like any brokerages, their customer service operatives vary quite a bit among themselves, too.)
FinPro Trading, the pure ECN broker would be the right choice. They charge $2/100k round turn commission and no extra charges for deposits and withdrawals. And most importantly 24*5 chat customer support.