After getting a set of Ultimate Ears Triple.fi 10vi, I knew I would probably never get a headset of such high quality. Unfortunately, it was only useful with my iPhone and I would never be able to enjoy using it as a headset with my computer. Thankfully, I learned many months later about a product called the "Headset Buddy" from a niche market group called Webko. Despite the cheesey sounding name, the Headset Buddy is actually quite a useful product.
I have two different "headset buddies"– one that converts the iPhone 4 pin headset adapter to two separate plugs, one for a mic and one for the headphohnes. I also have one that does the opposite and allows use of a regular headset with an iPhone. Using it is much like you would expect. It works flawlessly and the adapter allows for you to use whatever you want, when you want.
It's great. Now I can save room in my bag with my laptop and just carry my Triple.fi 10's with me and the headset buddy rather than my huge Logitech gaming headset. When I need to use the Triple.fi's with my iPhone, I just unplug it. That's all there is to it.
Conversely, if I want to use my Logitech set with my iPhone, all I have to do is plug it into the adapter and then into the iPhone. It's pretty bulky so I don't think I'll be doing that much, but it also allows you to use a regular set of headphones and a separate microphone if you want to.
Overall, I would recommend getting the headset buddy, especially if you could use your iPhone headphone system with a computer. It's nice and compact and relatively inexpensive, especially considering it could save you from buying two almost identical devices.