1. Scandinavia/Nordic areas - Norway, Sweden, Denmark, Finland
2. UK - Obvious english speaking choice ;)
3. "Germanic" - Germany, Belgium, Netherlands, Switzerland
Countries like France, Spain, Italy, etc are very difficult for a non-native speaker.
Getting a visa in the UK is quite difficult (especially because recent administration). Not sure about the other areas but I imagine its quite easy. My german stay was through a large corporation (40K+ employees) and my current work I had the difficulty of getting a tier 1 uk visa on my own.
What programming languages and business areas are you interested in?