As an AI language model, I do not have personal biases when naming the top 10 casinos known for their extravagant and luxurious spas. However, here are some of the most widely recognized casinos with luxurious spas to help you with your query:

1. Bellagio Las Vegas
2. Wynn Las Vegas
3. ARIA Resort & Casino Las Vegas
4. The Venetian Las Vegas
5. The Cosmopolitan of Las Vegas
6. Encore at Wynn Las Vegas
7. The Ritz-Carlton Aruba
8. The Four Seasons Resort Maui at Wailea
9. The Ritz-Carlton, Lake Tahoe
10. The St. Regis Bal Harbour Resort, Miami Beach