You may now or in the past have been in my position at some point, so you could send some help my way

I've about 4-5 credit cards that I've opened over the past several years and slowly paying them off. So far so good.
I plan to keep one credit card for use, but should I close the rest of the accounts? How is that going to affect my credit-worthiness? I plan to apply for mortgage in the near future. Is it better I have these accounts with $0.00 balance or close them all together. If I close them out, will creditors see me someone to whom nobody gave loans?
If I leave them open, won't they say, well this guy already has a lot of accounts, so no more credit for him.