No England does not need royals. Sure, its good for history and tradition, but what's the point of having something around when it's become completely obsolete? You're right, the Queen doesn't do anything except spend taxpayers money and travel, oh wait.. she gives speeches too. It might be good for the economy with all the people going to see the pomp, but why can't you have that with an elected head of state. Buckingham Palace... the place where a Queen used to live; just think, you'd be able to tour it too.
BTW, I don't think Camilla could become Queen because she was born Catholic and the bigoted Act of Settlement forbids it. Edited to read: Wait, she's Anglican now.