If I were to pick a few perks (as a junior developer) that would make me switch companies:

• Games in the lunchroom, so you can play a bit during morning and afternoon breaks
• Comfortable chair instead of "whatever the leasing company gives us"
• Fridge stocked with beverages
• Getting to order whatever programming books I need
• Non-tolerance for incompetent developers
• Company-sponsored team activities like paintball, lasertag, etc.
• Getting to be around good developers my own age
• Sponsored gym membership
• Flexible starting hours