Why would hording spirit make a challenge? I was a spirit whore most of my time leveling and it totally paid off regen wise. I mean, I could keep two people renewed indefinately in SM from all the regen. If you max out meditation, every 10.6 spirit is equivilant to 1 mana/5 seconds while casting. Untill MP5 gear becomes readily available, spirit is a priest's best friend.