You may ant to take a look at Audiobus too. I like the iRig HD too, you can connect ALL sorts of APPs with Audiobus. MultiDaw is pretty cool too. The IK APP has a cool little drum program, I think you'll like it. Thankfully the APPs are cheaper than the "real" Amplitude stuff.
 
Julien

 I have both the Amplatube 3 app and the Fender app for my iPhone. With the Iloud speaker it makes up one hell of a portable DC powered tone machine, but last week I did an experiment. I installed Amplaube 3 on my old P4 XP laptop. I used my IK Stealth pedal and ran the output to my tweed Champ 600. The installation was painless, one serial # "restore my gear" in the custom shop and it was all there, wish they could do that for the synths.
 The resulting tone was the most inspiring tone I ever heard. I played for hours.
 Big thumbs up for the iApps but in my book Amplatube for iOS  has been beaten by Amplaube 3 for PC on an old lappy with the Stealth pedal.

Hmmmm, I may have to try running Amplitube 3 out of my laptop, through my Focusrite Scarlett, to my Classic 50 in a clean setting....see what that sounds like.  Interesting idea Ohgrant.

I have a Microsoft Surface - installing now! :)
 
PS: I didn't realize until this thread the iRig would work via USB, so it looks like have a few options open now. thanks!

smallstonefan
I have a Microsoft Surface - installing now! :)
 
PS: I didn't realize until this thread the iRig would work via USB, so it looks like have a few options open now. thanks!

iRig HD and PRO do work via USB and with a little extra effort will work with Windows.  If you haven't seen this FAQ it may be helpful to you (though I'm not 100% sure if it applies directly to Surface - funny, though, I was recently discussing how I'd like to try one for mobile music to see if it fits "between" a regular laptop and the iPad stuff):  http://www.ikmultimedia.com/faq/3615

As I recall I tried Amplitube with this driver and had issues. I'm going to give it another shot when the iRig comes in, thanks!