I have only ever played in and DM'd campaigns in 3.5e, which is why most of my tips tend to cater a little more to the 3.5e way of thinking. I don't have anything against the other editions, I just don't know them as well. This doesn't mean I can't enjoy them though, I found myself during much of last year listening to podcasts from 3 groups based on 4th edition and one group has started moving into D&D Next (or 5th edition depending on who you ask). One group Thursday Knights ran a very long 4th edition campaign (124 episodes at about 5 hours an episode) that gave me the basic understanding of 4th edition rules. Another group Penny Arcade plays 2-3 times a year at PAX and they started as a 4e group and have moved on to 5e/Next with their DM Chris Perkins. Finally, a group that combines D&D and drinking called Crit Juice play through a 4e campaign as well.
So while I find 3.5e to be my home for D&D, the days (if not months) of time I have spent listening through these campaigns have given me ideas for elements to incorporate into my campaigns and how to improve my DM'ing skills. Of all the elements from these 4e podcasts, I really liked the concept of a minion, someone who's job it is to try and inflict some damage, but can be felled in a single hit. Currently in my large and small campaigns I'm working on developing some medium-to-large battles with many combatants. As a result, I find that having to track the HP for 40-60 combatants to be quite a sizable task, so I plan on taking the concept from 4e and "retrofitting" it to work for 3.5e.
Rather than having a 1-hit minion like 4e has, I figured a 2-hit minion could be more effective since minions in 4e have a tweak to their stats to make them hit harder but make them easy to be killed. Instead of having the minions hit harder it could still be valuable by being able to soak up a little more damage. Now, the one thing that I still will need to balance out a little bit would be if a minion took massive damage whether or not there should be a threshold of damage that would instantly kill the minion. Assuming that your party doesn't dish out massive damage all the time, this shouldn't be an issue, but it could potentially need to be considered. The nice thing about the 2-hit minions would be that you don't have to worry about the math and worry about all the HP, but rather you can focus on moving the enemies around and having them deal damage all while just marking those enemies with a tally or an x when they get hit and removing them when they're toast.
I would say that these minions are best suited with larger combats or in situations where you want to put some pressure on the party and create the feeling of a never-ending onslaught of enemies. At the same time, they could still be useful in smaller situations such as underlings to a more powerful monster/person and their only purpose is to provide flanking bonuses or to just be an inconvenience. They add some challenge to the encounter, but use your discretion when determining how much they factor into XP and treasure.