d100s are great to choose from big tables when stocking dungeons, picking names, and other such leisure.
But I don't like d100 Thief skills.
I'm a simple person, and rolling more than one die during play gets on my nerves as soon as it goes beyond simple "add the numbers together" or "pick the bigger/smaller number".
My players don't like d100 skills either.
There's been a lot of talk about Thief skills on many forums and blogs, and many alternatives can be found, from minimalist ones, to clusterfucks that make my head spin, to everything in between.
Here's my attempt at fixing it, inspired mostly by how AS&SH does it:
The skill check is resolved with a d12 roll + dexterity modifier, except for the Listen skill, which does not add any modifier. The skill succeeds if the result is equal or higher than the number in the table.