Good question. I find I have two primary modes: for a smoke-alone, more 'daily' accompaniment to either tedious work or reading, I really enjoy a fine Corona 42-44RG; for a sit-down, usually after-a-meal, conversation with friends smoke, I have a stable of 52RG sticks (from short robustos to toro-pluses, but I usually limit it to 6.5 inches or so) that I love. I find the 42s seem to have more focus and clarity, and the better 52s can have a magical complexity. I certainly enjoy other RGs, but those seem like two sweet-spots to me.
I can occasionally tolerate a 54+ RG (especially in a box-press), but they seem to tend to lose focus, and these 60+ behemoths just seem comical to me. On the other end, even a fine Lancero feels too much like sucking on a straw to me, and the ash is often so delicate, it seems too fussy for my taste.
Certainly available time is a factor in choosing, but my line of work demands lots of solitary time, so I can usually justify longer smokes while I'm working. Perhaps I'm fortunate that I usually choose my stick based more on the whim of what flavor profile I'm feeling in the mood for at the moment. "Gee, a Cohiba Genios with a Kahlúa and cream would sure hit the spot right now!"
There. There's a 52 I'll smoke even with no one around to talk with!
How 'bout the rest of you cigar nuts? What are your preferences?