I liked Agga, but not so much as mod_13, but he was still a favorite of mine.
Others like crocoduck and Mr. Friday who have left, I miss, but others who are gone for a time, like TimtheSkeptic seem to come online out of the blue for a time being. I like Irish too - it's good to see him coming back every now and then.
Some people who seem to just disappear I like to think they are just taking care of more important (real life) matters. Perhaps some are students in college, or others are just concentrating on work or (in Tim's case) moving, etc. Saddly, some like Hermes seem to be gone for good, but right now I am going to optimistic and hope that Velkyn, Omen, Alz and Nam just need some time away, and will return at some point in the future.