For me:

Season 4
Season 3
Season 2
Season 1
Season 5
Season 7
Season 6

2 - "Ladies of the Evening"
4 - "Yes, We Have No Havanas"
3 - "Grab That Dough"
1 - "Job Hunting"
5 - "72 Hours"
6 - "Henny Penny -- Straight, No Chaser"
7 - "Questions and Answers"

I've also listed my FAVORITE episode from each season.

The first two seasons kinda run neck and neck, and season thee isn't far behind. Then it would b the fourth season. Seasons 5, 6 and 7 probably would follow in that order. Those last few were OK, but the difference in quality compared to the other seasons is pretty evident. When my other half and I pop in DVDs, it's never the later seasons.

Here's Mine: Favorite to Least Favorite:

Season 3 (Standout: The Housekeeper)
Season 2 (Standout: Whose Face is This Anyway?)
Season 1 (Standout: Break-In)
Season 4 (Standout: Yes, We Have No Havanas)
Season 7 (Standout: Journey to the Center of Attention)
Season 5 (Standout: Not Another Monday)
Season 6 (Standout: Wham, Bam, Thank You, Mammy)