In order of yumminess:
1. (live) uni - usually reserve this for my dessert
2. shrimp boat - shrimp + crab meat + masago + raw quail egg + dash of tabasco sauce. This would be first, but nothing beats live uni.
3. scallop nigiri - the small scallops mixed with mayo and masago.
Tips for choosing sushi restaurants:
1. stay away from buffets
2. make sure the restaurant is owned by Japanese
3. spend your bankroll on dinner (optional)