I have to say, though, that some of the best times were as the healer in a regular 5-man heroics group in the early stages of each expansion. In a group of regulars, there are no worries about schedules or signups or loot rules. You know your groupmates will be online at the top of the usual hour, and you know you're in for an entertaining evening of challenging content with a group of good friends. To be frank, the experience spoiled me. Back in the EverQuest days, I used to love meeting new people in pickup groups with my bard, but pugging in WoW seems pale by comparison. I love my regulars, and if I can't have 'em, I go alone.
Beyond the context of guild tags and guild events, do you play with a partner or small group of regulars? Or is your pattern more a mix of guild events, pugging, and solo play?