Norton IS:
Norton Internet Security offers decent protection but the Norton slow down the system.
ESET SS:
ESET Smart Security offer awesome protection, Even i am also using ESET SS i didn't find any BUG.
If you are planning to buy a New AV i would be suggestion you to buy ESET SS as it offer Good Features with awesome protection with great lightness.
if you are advanced user ESET would be the best choice.
Kaspersky IS:
Kaspersky offers very awesome protection. But Kaspersky slows down the startup, its affect on startup is minor. which i would neglect.
If you are an intermediate user & want good protection, i would be suggesting you to use KIS.
& if you are an advanced user i would suggest you use ESS, you can use Interactive Mode in HIPS & Firewall for better protection.