Is it true the "prayer" + "belief" = "whatever you ask for"?

Mark 11:24  "Therefore I tell you, whatever you ask in prayer, believe that you have received it, and it will be yours." Anything you need -- money, love, happiness, you name it -- I am here to provide it for you.

Jesus made many claims that God would answer prayer.  He taught his disciples that what they needed was faith, belief and in some cases 2 or more people to agree with them in prayer.  Is this true?  Do christians see evidence of prayer producing miracles?  Can believers get "whatever" they ask for in prayer by "believing"?  Do we see evidence that god listens and answers specific prayers?  Are answers to prayer lists a common occurence?  Why do churches pass an "offering plate" to pay salaries and pay for building expenses when all that would be necessary is prayer?  I have never met a paralyzed person who did not pray moment by moment to be set free from their paralysis, and yet in 35 years of working with patients with spinal cord injuries I have never met one that god "healed" and allowed to walk.  I am not a skeptic, I am a realist living in the world as I observe it.   

Why won't God heal amputees?

http://www.whywontgodhealamputees.com/bible.htm

Thought provoking web site.  Very well written.  Fundamentalist christianity leads one to believe that with enough faith and prayer God will heal.  Many people have felt like God abandoned them or didn't love them when their miracle did not come.  As a nurse, I see surgeons healing, I see doctor's healing with medicine, but I don't see God reversing dementia or renewing lost kidney or organ function.  I don't doubt that there are miracles, but in 35 years of nursing I have not seen one.  What I do see are people that need good medical care in order to live long productive lives.  I don't question people's faith in Jesus or God to heal, but as a society we have to accept that lack of good medical care is inhumane.