[rubynerd]

The font is Segoe UI, I did that screenshot before I bought Proxima Nova, so the font will become Proxima Nova (I may Instapaper this and give you a bazillion settings for it)

As for the icons, they are a very tricky subject, I intended to create symbols for major features such as Funnel and Triage and have common icons for everything else, but it seems I've failed there

Which icons don't you like?

[sudonim]

Typekit gets you Proxima Nova as part of their package among others fonts. It's not bad, but for something like email, it may be helpful to use the standard stack of fonts.

My app sends emails (not a competitor). The interface uses proxima nova, but the email rendering is generally in an iframe with default sans-serif or serif font-faces.

If you use sans-serif as the first font-face that will default to Helvetica on Macs and Arial on Windows.

[cmelbye]

I generally don't like toolbars with lots of icons that don't have labels. Google's web properties have been moving in this direction and I find myself having to click buttons to figure out what they do.

[rubynerd]

How do you feel about hover-over Twipsy sort of things?

So when you hover over, a tooltip appears underneath the icon?