Best wire framing tool

I would say OmniGraffle for mac. You could also have a look at Axure (http://www.axure.com/).

Or have a go at this (kind of old) list http://www.creativebloq.com/wireframes/top-wireframing-tools-11121302

Smashing Magazine just posted a tip about this tool: http://www.infragistics.com/products/indigo-studio

For the Mac, without a doubt OmniGraffle v6. It's expensive at $199, but nothing on the Mac or the Web comes close.

Thank you for the answer.

+1 on OmniGraffle, but I'd add that whereas earlier versions were good, it's only with the recently released OmniGraffle 7 that the product has dedicated UX tools for wireframing. It's the latest version that makes it the clear leader at this, IMO

+1 on Axure RP 7 If you want to prototype a working mobile/responsive app or website. Lots of UI libraries (i.e. iOS7) to create and iterate on an app and even export helpful docs/sitemaps. You can easily create flowcharts, sitemaps and other UX docs in there, but it's not the core focus of the software.

However, if you want a stack of static wireframes that are not a working prototype Omnigraffle works well and has good resources such as graffletopia.com and wireframe templates from konigi.com

In my experience it's easier and generates more feedback to show an updated prototype app to stakeholders than it is to go through another round of static wireframe changes.

I will check them both out and see which works best for my style. Thanks you for the advice.