Wow, that's a tough question, because there are so many rig possibilities in amp sims like AmpliTube and Guitar Rig. For clean sounds in AmpliTube 3, I like the '65 Twin Reverb model, which is part of the (separately purchased) AmpliTube Fender
collection. For crunchy and distorted sounds, there are so many options that I don't have a clear favorite. A place you might want to check is IK Multimedia's "Preset XChange," which is web page (accessed from your IK User Area page) where people upload and download presets that they've designed.