Should Users see ID's?

[jmcilhinney]

I use GUIDs instead of numeric IDs, I would suggest others do the same.

There is a cost to using GUIDs over ints or longs so it's not something everyone should do just because. It's pretty much a must if you have IDs being generated at different sites, unless you use partitions to ensure no duplication, but for your average single-server and especially single-user system, there's no real benefit to using GUIDs.