Sennheiser PC163D for every day gaming as they are light on the head and easy to forget your wearing combined with a decent mic and sound quality that while not in audiophile league is good enough not to find anything objectionable with and can pick out sound detail, etc. that most headsets like those made by plantronics, razer, etc. just don't do.
Sennheiser PC333D - for shorter periods of competitive gaming, etc. the extra mic functionality is really handy to have.