I thought that this review was interesting because of the headphones compared. On one hand we have entry-level audiophile equipment from a world renowned company in audio equipment and on the other hand we have the Medusa's from speedlink, when as far as I know is only known for its over-rated razor mouse line. Comparing these two pieces of audio equipment is like comparing a balanced combat knife to an above-average Swiss army knife. You likely don't want to hunt with the Swiss army because the knife isn't sharp enough, and you likely don't want to try and be MacGuyver with the combat knife because it only cuts. In the same vein, I wouldn't use 5.1 noname headphones for music listening, but I also wouldn't use stereo headphones for a scifi or action movie (I would use my 5.1 home theater).
Despite the mis-matched comparison, for the intent of the review the products are seemingly appropriate. The review seems fair, the reviewer noticed every time the senns produced higher quality sound and when having 5.1 made helped spacial recognition in gaming/action movies.
I also thought that it was interesting that the reviewer found that 5.1 sound actually helped. In my gaming experience I have found stereo to be just fine as most 3d games have audio engines that simulate noise coming from different directions, and furthermore sound card developers like creative have spent millions on R&D developing technologies (like EAX) that revolutionized 3d audio in gaming and a lot of that work has been geared towards stereo due to 5.1 gaming never really catching on. I always thought 5 speakers for a PC was a little odd because I have never seen a computer setup where I could properly place all 5 speakers. The rear speakers seem to be brutally inconvenient to place unless attached to the back of a lux armchair.
I thought it was odd that you said you absolutely didn't hear some sounds (things from behind) in some games. That's either PEBKAC (not telling the game/sound drivers that you are using stereo headphones) or poor sound engine design. Something like that shouldn't be an issue IMHO. It is the intent of 5.1 sound to give properly placed natural sounding audio, not "extra" sounds.
Over all it seems that there are few 5.1 headsets and those that exist aren't exactly quality. Based on the review I think that I would always pick a stereo solution as there are more options available and much higher in quality.
Some people in this thread have been speaking about headphone amps and I thought I would comment a little.
The Sennheiser HD555's in their current revision have a nominal impedance of 50ohms. These do NOT require a headphone amp, but would ABSOLUTELY benefit sonically from the use of one.
I think there were older revisions of the HD555's which had different impedances, one being 120ohm. An owner of this revision would really want to think about getting an amp and might find them quiet with out them.
200+ is where you really MUST have an amp, but a general rule of thumb is that if the headphones have a 1/4" TRS connector (the fat "phone plug") they would likely benefit from a headphone amp. Unless the amp is cheap, try the amp with your headphones first, you might not see any improvement at all and you would see your money go to waste.
$200 USD is not the cheapest headphone amp you can find. There are DIY headphone amps out there called Cmoy amps, which are named after its inventor Chu Moy. You can google cmoy and find instructions including schematics, or you can ebay the same query and find them for sale at around $50 USD. This DIY amp is credited for being cheap while producing audiophile quality amplification.
Aside from the DIY stuff, headphone.com (Headroom) sells two different headphone amps <$200. The first is for $100 USD, and the other has a USB interface so you can use it as a sound card (and have it bypass annoying OS generated sounds) for $150. Most non or entry level audiophiles should find these amps suitable.
I ended up writing this twice, you guys took your forums down sometime between the time I read the thread and when I was posting. And then there was a DB error!Tisk Tisk!
. Probably going for the 555's myself.