Here's an agenda custom command that acts as the main interface I interact with org (in fact, emacs :)).
(setq org-agenda-custom-commands
'(("c" "Simple agenda view"
((agenda "")
(tags "PRIORITY=\"A\""
(org-agenda-skip-function '(org-agenda-skip-entry-if 'todo 'done))
(org-agenda-overriding-header "High-priority tasks:")
))
(tags-todo "PRIORITY=\"C\""
(org-agenda-overriding-header "Long-term:")))
(alltodo ""
((org-agenda-skip-function
'(or (zongheng-org-skip-subtree-if-priority ?A)
(zongheng-org-skip-subtree-if-priority ?C)
(org-agenda-skip-if nil '(scheduled deadline))))
(org-agenda-overriding-header "Other tasks:")))
))))