Hello I use TwistedWave. It's work well and the developper is very very reactive.

I would recommend Amadeus. It's the closest thing I've found to resemble SoundForge, (which is the only Windows app that I miss with all my heart. ::tear::)

It helped that Amadeus was used as a teaching tool by one of my profs in Electroacoustics. The incredible things he could demonstrate (and compose, on a microscopic level) by only using: copy, paste, fade and gain commands. Once you learn the shortcuts, it's a zippy little app.

Not too stiff on the wallet, either.

Amadeus by Hairersoft.

I'm a big fan of Wave Editor. In fact, I used to loath sample editors until I started using it a couple years ago (around v1.2... they're at 1.4.6 now) and did all my sample editing inside a multi-track DAW. The developers themselves are studio guys and are not only responsive to the needs of users (they participate in the forums), but they themselves keep in mind what the product is being used for and try not to overload it with frivolity, mainly so they can keep their own sessions flowing. The support desk built into their apps is pretty cool, too, with someone getting back usually in 3-4 hours, sometimes up to a day.

In keeping with your needs you stated above, all of the developer's products support both VSTs and AUs. While you can't make a "layer" template per se, you CAN create a .wedt file (wave editors native file format, which includes all the layer, non-destructive editing, effects, & etc. info) with as many pre-built layers and effects and markers as you want. Save that and open a copy every time you want to use it as a template (or check "Stationary Pad" in the finder Get Info window, which will cause the opening program to request you save a duplicate of the file before editing).

Editing's pretty quick and painless. Just be sure to enable whatever you want or need from the view options menu, otherwise you might think (quite justifiably) you're missing something. While they are lacking on shortcut keys for some basic editing function, they have a shortcut key editor that allows you to customize the keys and add a shortcut for ever menu item.

One thing that throws newcomers off is fades. They get bogged down with the fade editor (in the layers menu->add fade), thinking it's the only way to create and/ or edit fades. While it is pretty powerful, don't overlook the corners of the smart edits which, depending upon your shortcut key, allow you to simply click and drag to create basic linear or logarithmic fades of any length up to that of the smart edit itself. You can also adjust and create cross fades in the same single-click and drag manner. There's a lot buried in the program and chances are if think there's an easier way to do something, there probably is.

BTW, Andrew, I just stumbled across your sound + design podcast on itunes not two days ago. For the three episodes you popped out it was very interesting. Will we see/ hear anymore?

I've played with Wave Editor a fair bit, but I can't seem to get in the flow with the app. I keep going back to it from time to time, but i've found app oddly processor intensive for no reason. It has been a bit more functional for me since I mapped better shortcuts, but it is still growing on me.