The S&S YS90DX is a good choice and I think the cheapest available. Your PT-10 does not allow hot wiring so the strobe is used in slave mode, meaning the internal flash from your camera will trigger it to fire. This connection is made via a fiber optic cable that attaches with a velcro patch. I've been using this same strobe for almost 2 years with no problems whatever.
Medic is right, the Ikelite 125 strobe is a bit stronger with a slightly wider coverage. Instead of a fiber optic cable you'll have a seperate aiming sensor to keep lined up, if you want to use the TTL capabilities of the strobe, I believe you'll also have to purchase a manual controller. Someone who uses Ikelite strobes will have to tell you the details.
There's also a new Inon Z strobe that's gaining alot of attention. I don't know what the prices are, though.
For a simple, easy to use, manual strobe with plenty of coverage for your camera, the YS90DX will serve you well. My opinion only but I've never regretted mine!