I like having rules for non-combat situations, but I believe that those rules should be relatively light.
I also think that the target numbers for skills should be static, so that what is challenging at low levels is a cakewalk at high levels and vice versa; I am not a fan of including skill checks designed to "challenge" PCs of a particular level. Not only does this make setting up encounters more difficult, but it makes it harder for the PCs to know how to react to the world. If the DCs of checks will always be roughly "roll a 10" if you can Take 10, and "roll a 20" if you can Take 20, then why not just say "Take 10" and "Take 20" for various checks, leaving the DCs and the skill ranks out of it?
EDIT: Because this sounds contradictory to what I wrote later, let me elucidate: the DC should be static relative to the level of difficulty. If the characters take actions to reduce the level of difficulty, this affects the roll or the DC, but only because the level of difficulty has changed. Thus, picking a lock is always more difficult than climbing a tree, and a 1st level rogue might not have much of a chance to pick most of the locks she encounters. Later, when she can pick most locks, this will show that the character has improved.
This is in contrast too, IME, what became the "ever moving mark" of 3e skill checks.
I think the thieves's skills in 1e modelled static chances better than the 3e skill system does in practice, but I like the format of the 3e system better. (Shrug) Nothing's perfect.
As for interactive skills (Bluff, Diplomacy, Intimidate, etc.), I prefer to have the player roleplay, and then use the check to determine how the words are taken. So, effectively, the results of roleplay determine the DC of the check.
I also do this for searching. If the player states he is looking under the pillow, then he will find the object hidden there. If he instead states that he is looking at the bed, there is a roll with a high chance of success. If he instead states only that he is searching the room, there is a roll with a moderate chance of success. If he just takes a minute to look around, there is a roll with a relatively low chance of success.
RC