For 10 man I would use single target heals and the associated Chakra.
Things are going smoothly, no worries. Take a sip of soda, or text your friend with one eye on the monitor.
Renew - Keep it running on your target of choice. (Tank usually)
Heal - Use as your main heal, saves your mana and refreshes Renew.
Power Word: Shield - Toss on anyone that needs it, keep using Heal.
Prayer of Healing - When a few of your group is injured, toss a Power Word: Shield on your tank, and take a moment to heal everyone up.
When your tank pulls a couple adds, and your NOT tank pulls a extra one.
Binding Heal - Casts faster then Heal, heals for more, heals you AND your target. Great mindless way to make sure you stay alive to blow more mana and pump up your targets HP bar.
Circle of Healing - Instant AoE team heal. Fast way to throw out some bandaids.
Prayer of Mending - Instant "AoE" heal. If you are in a bad situation and use this, it does all its healing quickly and saves some hide.
Holy Word: Serenity - Big, instant heal. Gives you a better chance to get "critical casts" which are VERY handy.
When you think half your team is gonna die.
Divine Hymn - Take a moment for yourself and cast this CHANNEL spell. Don't move, just think what your gonna do in a few seconds when the green bar is gone. In the meantime, watch everyone's HP bar jump up nicely. It makes you feel good for a moment.
Guardian Spirit - When someone is about to die, and you need a moment to
A. Get more mana, or
B. Heal someone else. or
C. Heal them again.
Use this and it will buy you a moment to stop the bleeding.
Fear - Scare those dummies away from you, show them your hideous face, or your @$$ and send em running for the hills.
Lightwell - Use this at the start of boss fights. Or other mass encounters. Straightforward.
Flash Heal - Wait to use this until it is a "Crit Spell" At which time it is INSTANT cast, and requires NO mana.
Greater Heal - Same concept as Flash Heal, but it will require LESS mana, and cast FASTER.
I feel for 10 people, or less (even 15) you should focus on single target healing. In mass raids or battlegrounds going the AoE route is not a bad idea though.