[TheAnswerMan]

Deciding between Debian/Arch is mostly about the package system. Debian locks in to package versions for stability. You don't need to worry about updating package A changing it's API and breaking package B. It's sort of a professionally managed package system. The downside is you might miss out on cool new feature of package A since you're locked in to an old version.

A lot of the big moving and shaking in Arch has already come to pass, so it's not likely you will brick your system from an update.

So if you are really into the latest versions of things, then Arch. If you prefer to remove the risk of breaking your system and limit updates to security patches then go with Debian.