Today I found out that you could directly upgrade from Ubuntu 6.06 Dapper Drake to 8.04. I know, I know... that should have been obvious given that they're both Long-Term Support releases. Anyway, moving right along... the instructions were found here and overall the whole process was very simple besides being constantly asked if I wanted to replace old config files with the newer versions. Looks like my concerns in this post were mostly moot, so far, no problems! *knock on wood*