Everyone's house-ruled this Feat. It's sorta like the unofficial hobby of 3E players. It's an initiation rite for these boards.
In general, I don't like Feats that just do something you could have done with skill points. Feats, IMO, should give new abilities you can't get through any normal process. So, IMC we made it more interesting:
***HOUSE RULE WARNING***
SKILL FOCUS (General)
Prerequisite: 5 ranks in the appropriate skill
You may Take 10 with the chosen skill even under duress. You may re-roll a skill check on a roll of 5 or less; the second roll stands.
GREATER SKILL FOCUS (General)
Prerequisites: Skill Focus, 10 ranks in the appropriate skill.
You may Take 10 with the chosen skill even under duress. You may Take 20 with the chosen skill even if there is a drawback for failure; the check still takes 20 times as long as normal. You may re-roll a skill check on a roll of 10 or less; the second roll still stands.
(This overrides Skill Focus)
The Take 20 thing works nicely. Basically, you spend 19 skill checks planning, then 1 doing. So, a Rogue with Disable Trap sketches out the mechanism in the dirt, figures out where to poke, and then does it perfectly.
Now, I'm not saying that this is what they should do in 3.5E. Keeping it simple is a good design philosophy, so just bumping it to a +3 will work fine. But, I just wish they had been more imaginative when they first started.