Have a look at the CRKT swindle, it's a really nice 'gentleman's folder' on a budget.
Gentlemen folders must be classy, not just a tool. Impress your friendsAs you want one hand opening (not sure you need a clip) then I suggest the following at around $100. If you are going to carry one knife make sure it is of the best, pride in ownership and you appreciate the makers art when using a good knife. Al Mar Hawk Ultralight - $95http://www.knifeworks.com/almarhawkultralightstandar338closed.aspx Spyderco Chaparral - $102http://www.amazon.com/Spyderco-Chaparral-Plain-Carbon-6-37-Inch/dp/B005CVHCNA/Upper Midrange = Spyderco Delica, Dragonfly, UKPK etc. If you want to step down a bit then look at the Kershaw Leek, the RAT Model II or the CRKT Lake. (Cheap, Cheaper, Cheapest) There are hundreds of knives in this category but the ones above are my choices for this type of need.
Really there are many many choices that fit your requirements.